Ⅰ.根据首字母或括号内提示，写出单词的正确形式
1. A n________ is the member of an aircrew who is responsible for the aircraft's course.
2. The spacecraft is o________ the moon and it will land on it in a few hours.
3．A Chinese a________is sometimes called cosmonaut.
4．The train's about to leave. All a________！
