Henry and Bill are good friends, but they ____ （从不） see each other. They come from different ____ （国家）. Henry is from the USA, Bill is from England. They ____ （两者） have computers and talk on the Internet. Today they talk about how to keep in excellent ____ （状况）.

    Henry thinks doing ____ （锻炼） is good. He is a ____ （成员） of a sports club. His ____ （梦想） is to be a football player. He also thinks good eating habits are important. Fruit and vegetables are his ____ （最爱）. He doesn't eat fast food, though it ____ （闻起来） delicious. Bill ____ （赞同） with Henry. He often plays sports and eats healthy food, too.

在使用光学显微镜时，下列叙述正确的是（    ）