1、My watch ______ at nine o'clock but now it _____ .

问题描述:

1、My watch ______ at nine o'clock but now it _____ .
A went stopped B was going stopped
C was going has stopped
为什么用C不用B
2、Now rememeber ,you ____ the text until the teacher tells you to .
A could not star B are not to star
为什么用B 不用A?

1题 题目中的now说明:想要强调的是九点还在走着呢,可‘现在已经’不走了,所以用完成时.2题不太明白……