The students didn’t manage to work out the problem ______ their teacher had explained how.
问题描述：
The students didn’t manage to work out the problem ______ their teacher had explained how.
A. when B. untilC. unless D. as
1. Some people think ______ about their rights than about their duties.
A. too muchB. as much C. much moreD. many more
答
B
C
原因自己想