there have been many changes_____in my hometown in the last twenty years.there have been many changes_____in my hometown in the last twenty years.A.happen B.happened C.happening D.to happen
问题描述：
there have been many changes_____in my hometown in the last twenty years.
there have been many changes_____in my hometown in the last twenty years.
A.happen B.happened C.happening D.to happen
答
B.happened
从后面的in the last twenty years.来确定这里的时态，应该是过去发生的事情了，所以用happened 这个动词过去时。
答
应该选C
答
C
happening动词ing形式happening in my hometown 修饰前面的changes
答
B 后面到hometown是定语修饰changes A显然不行C正在进行的动作D将要发生的动作