When he was a little child, Andrew had a serious bad habit of sucking（吮吸） his fingers all day long, especially when he had nothing interesting to do: when he was sleeping, when watching TV, when sitting on the sofa and so on. At the beginning, his parents didn't think it was a bad habit.

Therefore, as time goes by, the boy couldn't give up his habit. Now, in his twenties, Andrew seems to have developed the bad habit into another one: he always bites his nails(指甲). He cannot stop biting his nails all the time. There're moments when he even doesn't know that he is doing it. He realized it was a problem and this worried him a lot. Some of his friends told him about this bad habit, and he stops for a while. But then, if he isn't busy doing something, he starts biting his nails again!

In fact, there're a lot of bacteria(细菌) in your nails and they can cause some disease. Also, the nails will become ugly and hard to recover. The worst thing is that this bad habit will bring the mental illness（心理疾病）. If people cannot correct it in time, it can affect man's mental health.

In short, bad habits are very worrying, especially when the person with the habit is in public and cannot stop himself or herself doing it. Still, there must be ways to give up these bad habits and these people should try their best to stop doing them.

     It was my first time in the US. I think there is no other country that I have heard so many things about before I visited it. Burgers, big cars, fat people, good wine and fantastic cities. For sure the real experience was quite different. Although you can find all these things there, you will also find many other things to discover.

     In Los Angeles, I stayed at a place where they even produced home-made videos. I always thought in Hollywood only movies with lots of money are produced. But in this place, even parts of the living room were functioned (运作) into a scene. But anyway, this shows what you imagined about a place before arriving might be totally wrong. Now I started to understand the city is not only the place where the big movies are made, it's also where people are crazy about movies, and always try to start a production even if they don't have lots of money. People there just really love movies, they are motivated (调动积极) to give their ideas a try and at least open up a channel online with their home-made stories.

     Of course, there are many other interesting places in Los Angeles. As I stayed only a few days, it was not enough time to see all. But I advise you to have two apps on your smart phone for traveling in America. First is Yelp to find the closest and best restaurant or coffee place. And the other is Uber because especially in Los Angeles, you won't find taxis and everything is so far. You can also drive but it's wise to park your car close to a subway station and go to Hollywood by subway.