国家对实施首检的起重机械制定了目录，下列起重机械中实施首检的起重机械是（）。

A.桥式起重机

B.塔式起重机

C.履带起重机

D.桅杆起重机

根据句意和首字母提示补全下列各句中的单词。

1. He is very o______, because he likes talking and laughing.

2. My father u______ to be a teacher, but now he is a writer.

3. He has c______ a lot. Because he is different from the past.

4. I am not afraid of the d______. I dare to go out.

5. I often send and receive e______ on the Internet.