When the weather is hot, you go to a lake or an ocean. When you are near a lake or an Ocean, you feel cool. Why? The sun makes the earth hot, but it cannot make the water very hot. Although the air over the earth becomes hot, the air over the water is still cool. The hot air over the earth goes up. Then the cool air over the water moves in and takes the place of the hot air.

    Then you may ask, "Why is the ocean full of salt?" Scientists will say that the salt comes from the rocks. When the rocks get very hot or very cold, they crack (爆裂). Rain falls into the cracks. The rain then carries the salt into the earth and into the rivers. The rivers carry the salt into the ocean. And then you may doubt, "But the ocean does not get more salty every year. Scientists are not sure about the answer to this question.

    We know a lot about our world. But there are still many answers that we do not have, and we are curious about them.

Where would you like to stay when you go on a vacation? What kind of hotel would you like to choose? Different people have different ideas. In fact, there are all kinds of special places to stay when you go on a vacation. There are hotels, motels, youth hostels, B&Bs (bed-and-breakfast), home stays, and more. Each is for a different kind of people. If you travel by car, a motel is good for you. You can park your car outside your room. A youth hostel is good for young backpackers (背包客). A B&Bs might be best for couples (夫妻) or anybody who doesn't like being noisy.

    For people who like reading, the library hotel in New York is a must-see. Each of the hotel's 60 rooms is full of books. In fact the hotel has over 6, 000 books in all. If history is your thing, the 9th floor is for you. If you are interested in math and science, you can stay on the 5th floor. Artists will feel at home on the 7th floor. The Poetry Garden is on the 14th floor, and there is a cozy sofa in it. You can sit on the sofa and enjoy reading a good book or relax outside in the Poetry Garden.

Do you feel guilty(内疚的) for something you did? Maybe you made a mistake that hurt someone. {#blank#}1{#/blank#} Either way, the simple words "I'm sorry" can help you and others feel better. It's not always easy to admit(承认) what you did is wrong. But you can't learn from your mistakes without admitting them.

Apologizing(道歉) is an important part of personal growth. When you apologize, the other person knows that you understand his feelings. {#blank#}2{#/blank#} But in fact, it shows that you are strong enough to put others before yourself. After apologizing, you may become closer to your friend than before.

But even after you decided to apologize, you may not be sure how to do it. {#blank#}3{#/blank#}

①Show that you feel guilty and understand how the other person feels. For example, you could say, "{#blank#}4{#/blank#} I feel terrible for talking to you like that."

②Don't keep doing what you apologized for.

③Don't put off(推迟) making an apology.{#blank#}5{#/blank#}

Apologies can be hard, but they are necessary for healthy relationships.

① Do you have a dog? What can your dog do for you? Do you know that dogs can read our feelings? Now some people find that dogs can smell (v.闻到; n.嗅觉) people's stress (压力).

②Dogs really are man's best friends. They have special smell. A new study said that dogs can smell if people are feeling stressed. Teachers at Queen's University, UK, made the study. They got breath(呼吸)and sweat(汗) from people both before and after doing a hard maths problem. They looked at the people's heart rate (心率), blood pressure (血压) and stress feeling in the study. Dogs can smell the difference in breath and sweat from people. Then they can know when people are stressed.

③The finding is wonderful: the dogs found stress in 675 of the 720 people. It could be 93.75% right! Australian News reported. The study's writer Clara Wilson said, "stress can change people's breath and sweat. Dogs are very good at smelling these changes." In the study, she also said, "this finding helps us learn that how dogs may know people's feelings."

④ This finding shows how special the bond is between people and dogs. The finding also tells us that dogs are very clever. And maybe dogs can help stressed people.