下列词语中，没有错别字的一组是（      ）

家蚕吐丝的目的是为了给人类提供纺织原料．

Dear Pet,
   Without knowing more about you, it's hard for me to give you some good advice.
   But first, I am sure that you are1 . You said that nobody would care if you left home. What about your2?  And other family members? It seems that you are very3 . You'd better go to a doctor or talk 4 your parents. They will be able to help you.
Second, I'm sure there’s someone else in your class who feels lonely, 5. You never know6other people feel. Try to make friends with your classmates. And you could7a club to meet new people and make friends, too.
   You8find happiness in yourself. So my9advice is to write a list of all the good things about yourself, learn to like yourself, and then10 will see your confidence (信心)and like you, too.
                                                                                                                                                                                  Editor

There must be something wrong with the TV. We can see nothing on the ____ (屏幕).

一水库存水量一定，河水均匀流入水库内．5台抽水机连续抽10天可以抽干；6台同样的抽水机连续抽8天可以抽干．若要求4天抽干，需要同样的抽水机____ 台．