回上一层第二部 第一课 --- 请重复跟读，直到可以於声音档的留空之间唸完整句為止；熟练之后您必将可以 "脱口而出" 地说出标準的美式英语
- at least
- You should read at least one book a month.
- I am poor, but at least I follow the law!
- at once
- Einstein wanted to start working at once.
- How can you do so many things at once?
- at one time
- Ian was at one time so devoted to playing the piano.
- Jeffrey dribbled three balls at one time.
- at present
- At present, I still don't want to retire.
