1. He began to work there ____.
A. on his fifty B. at the age of fifty C. when he fifty D. in his fifties
为什么选D???求理由~~~
2. They moved to Beijing ____.
A. in 1980s B. in the 1980' C. in the 1980s D. on the 1980's
为什么选C???求理由~~~
3. She was ____ her early twenties when she went abroad.
A. at B. on C. of D. in
为什么选D???求理由~~~
望高手解答、好的追加