I know that there are times when friends are apart for a while – or even forever – and that your lives take different paths. Yet, I always hope for a happy ending. I know that friends reconnect again when it makes sense.

    My friend Julie and I had a long period in our friendship. We used to see each other daily. I would eat brown rice in her kitchen while we shared our secrets.

    Later, we celebrated each other's weddings. My husband and I welcomed Julie's first son (born on my birthday). By the time he was learning to walk, Julie and her family had moved to another city. We spoke on the phone sometimes and exchanged Christmas cards.

    After they welcomed their third son, they moved to Edmonton, which is a farther city. We haven't seen each other since then. They changed their phone numbers. I received a letter from her, but I couldn't find that envelope later. I e-mailed her a few times, but didn't get a reply.

    It was painful not to be in touch with an old friend. I let it go. I knew that Julie and I would reconnect again, when it made sense.

    Last year, Julie's husband got in touch with me on Facebook. I felt something bad, and soon my feeling proved true: Julie had passed away the month before. She died of cancer.

    I regretted that I had not been part of Julie's support system, or the last years of her joyous, painful time on Earth. I cried. I'm so sorry, Julie, for counting on more chances.

    Last week, I donated my hair in memory of Julie to make wigs (假发) for cancer patients. It was a small way of showing that I loved her and will never forget her. And that I look forward to us reconnecting again – when it makes sense.

    Like many other people, I love my smart phone, which keeps me connected with the larger world that can go anywhere with me. I also love my laptop，because it holds all of my writing and thoughts. In spite of this love of technology, I know that there are times when I need to move away from these devices and truly communicate with others.

    On occasion, I teach a course called History Matters for a group of higher education managers. My goals for the class include a full discussion of historical themes and ideas. Because I want students to thoroughly study the materials and exchange their ideas with each other in the classroom, I have a rule —no laptop, iPads, phones, etc. When students were told my rule in advance of the class, some of them were not happy.

Most students assume that my reasons for this rule include unpleasant experiences in the past with students misusing technology. There's a bit of truth to that. Some students assume that I am anti-technology. There's no truth in that at all. I love technology and try to keep up with it, so I can relate to my students.

    The real reason why I ask students to leave technology at the door is that I think there are very few places in which we can have deep conversions and truly engage complex ideas. Interruptions by technology often break concentration and allow for too much dependence on outside information for ideas. I want students to dig deep within themselves for inspiration and ideas. I want them to push each other to think differently and make connections between the course materials and the class discussion.

I've been teaching my history class in this way for many years and the evaluations reflect student satisfaction with the environment that I create. Students realize that with deep conversation and challenge, they learn at a level that helps them keep the course materials beyond the classroom.

I'm not saying that I won't ever change my mind about technology use in my history class, but until I hear a really good reason for the change, I'm sticking to my plan. A few hours of technology-free dialogue is just too sweet to give up.

    There is an old saying about volunteer work that goes like this: “ No one can do everything, but everyone can do something.”

    Today, many people volunteer their time and energy to help others. There are a lot of ways to meet other people's needs. For example, some volunteers provide help after a disaster. Others are happy to get dirty while repairing homes or planting trees or flowers in poor neighborhoods. Young people see suffering and loneliness around them and find ways to help. And history lovers help archeologists(考古学家) search for ancient objects to help deepen our knowledge of the past.

    Volunteers work in many areas around the world, including Haiti. More than four years have passed since a 7.0 earthquake shook the nation. The exact number of people who died may never be known. Thousands of survivors of the Haitian earthquakes still live in temporary shelters. Last year, former American President Jimmy Carter and his wife Rosalynn joined five hundred volunteers in the town of Leogane to build houses.

    Organizations do not have to be large to get volunteers. An activist group in Dharamsala, India is a good example, Jodie Underhill from England arrived in northern India several years ago. She planned to volunteer for an environmental project. She could almost not believe how much rubbish was ruining some of the area's most beautiful sights. Jodie Underhill learned about how to deal with the rubbish while taking part in other volunteer projects. But soon enough she formed her own group, Mountain Cleaners. Jodie Underhill says the work is very hard. But she praises the group's efforts as a wonderful experience. The young Englishwoman says the Indian media started calling her “Garbage Girl”. And she says she was pleased with the name.

    American teenagers also volunteer in many ways .

    Last year, around Labor Day, I read a “Happy Ad” in our local newspaper. There was a lady in a local nursing home for the aged, who was celebrating her 90th birthday and her family wanted everyone to know about it. It said that if you wanted to drop her a line, here was her address. So I did. I found a birthday card and dropped her a short note, wishing her a happy birthday.

    A week or so later, someone knocked at my front door. I opened the door and found a middle-aged man standing on my doorstep. He introduced himself as the son of this woman to whom I had sent the card. He explained that he just wanted to drop by in person and thank me for sending such a nice card to his mom. Apparently, like many older folks, she did not receive much mail and was quite excited to receive mine. I just didn't know what to say. I told him it was my pleasure and that I hoped his mom had enjoyed her birthday.

    That year, I did not send out any Christmas cards, except to this lovely old lady in the nursing home. I just told her that I was thinking about her and hoped that she had a nice holiday. I sent her a holiday card and also a couple of notes in between. I just thought she might like to have someone write to her, to get some mails.

    She passed away a couple of months ago. I never met this lady, but I did keep her and her family in my thoughts. I dropped them a line of sympathy. I hope that my few little notes were enough to brighten a couple of her days here on earth.

    Our plan was to drive into Cambridge, catch the 7:34 train to Liverpool Street Station, then to separate and meet again for lunch. We should have arrived at Liverpool at 9:19, but due to a typical London fog, the train had to move along so slowly that it was not until 10:30 that it got there. In spite of our late arrival, Joan, my wife's sister, decided that she would go to see the Crown Jewels in the Tower of London while we went shopping. It was only after her sister had disappeared into the fog that my wife realized that we hadn't decided where we should meet for lunch. Since I had our three tickets for the concert in my pocket, this was indeed a problem. There seemed to be nothing we could do except taking a taxi to the Tower of London, and try to find her there. Needless to say, we didn't find her.

    It was now one o'clock, and the concert began at 2:30. "Perhaps she will think of waiting outside the concert hall," suggested my wife hopefully. By this time the fog was so thick that road traffic had to stop, and the only way to get there was by underground railway. Hand in hand we felt our way along the road to where we thought the nearest station should be. An hour later we were still trying to find it. Just as I was about to lose my temper completely when we met a blind man tapping his way confidently through the fog. With his help we found Tower Hill tube station just fifty yards down the road.

    By now it was far too late even to try to get to the concert hall before the performance began at 2:30, so we decided to return to Cambridge. It took seven long hours instead of the usual two to make that journey. Nor were we able to get any food and drink on the train. Tired and hungry we finally reached home at ten, opening the door to the sound of the telephone bell. It was Joan; she had seen the Crown Jewels, had managed to get another ticket for concert, and had had a wonderful dinner at a restaurant near the hotel where she decided to stay for the night. Now she was ringing to discover whether we had had an equally successful day.

    I'd done it before, and so I had no reason to believe that this time would be any different. I was sure that when I returned home from my mission trip. As always, I'd bring back nothing more some mud on my boots. A hole or two in my jeans and, of course, a lot of great memories.

    The summer before my high school graduation, I went to West Virginia with others as volunteers to repair the homes of those in need. Arriving at our destination, my group was assigned the task of rebuilding sections of a home that had been damaged by fire. No sooner had we parked on the home's dirt driveway than we saw an excited little girl, no more than six years old, standing in the doorway of the family's temporary home. Shoeless and wearing dirty clothes and the biggest smile I'd ever seen, she yelled, "Ma, Ma, they really came!" I didn't know it then, but her name was Dakota, and four more days would pass before she'd say another word near me.

    Behind Dakota was a woman in a wheelchair — her grandmother, we'd soon learn. I also discovered that my job that week would be to help change a fire-damaged dining room into a bedroom for this little girl. Grabbing our tools, we went to work. Over the following days, I noticed Dakota peeking at us every now and then as we worked. A few times, I tried talking with her, but she remained shy and distant, always flying around us like a tiny butterfly but keeping to herself.

    By our fifth and final day, however, this was about to change.

    Before I went to work on her home on that last morning, I spoke for a moment or two with the grandmother. I was especially pleased when she told me how much Dakota loved her new room — so much, in fact, that she'd begged to sleep in it the previous night, even though it wasn't quite ready. As we talked, I noticed something I hadn't seen before — Dakota was hiding behind her grandmother.

    Cautiously, she stepped into view, and I could see that just like her clothes, her face was still dirty. But no amount of soil could hide those bright blue eyes and big smile. She was simply adorable. I wanted so much to hug her, but respecting her shyness, I kept my distance.

    Slowly, she began walking toward me. It wasn't until she was just inches away that I noticed the folded piece of paper in her tiny hand. Silently, she reached up and handed it to me. Once unfolded, I looked at the drawing she'd made with her broken crayons on the back of an old coloring book cover. It was of two girls — one much taller than the other — and they were holding hands. She told me it was supposed to be me and her, and on the bottom of the paper were three little words that instantly broke my heart. Now almost in tears, I couldn't control myself anymore — I bent down and hugged her. She hugged me, too. And for the longest time, neither of us could let go.

    By early afternoon, we finished Dakota's bedroom, and so I gladly used the rare free time to get to know my newest friend. Sitting under a tree away from the others, we shared a few apples while she told me about her life. As I listened to her stories about the struggles she and her family went through daily, I began to realize how boring various aspects of my own life were.

    I left for home early the next morning. I was returning with muddy boots and holes in my Jeans. But because of Dakota, I brought back something else, too-a greater appreciation for all or the blessings of my life. I'll never forget that barefoot little butterfly with the big smile and dirty face. I pray that she'll never forget me either.