1 . Sharks are ______ _______ ________(在……顶部) of the food chain, so if their numbers drop, the ocean’s ecosystem will be in danger. （根据汉语提示完成句子）

2 . Even today, when some people have very informal styles of greeting, they still use their hands as ________ ________ ________ trust. （根据课文内容填空）

3 . Indeed, body________ are part of what we call “body language”. （根据课文内容填空）

4 . I’ve visited some beautiful cities, but this is one of the ________ ________ places I’ve been to. （根据课文内容填空）