What were you doing when the bell r_____?

问题描述:

What were you doing when the bell r_____?
Please c______the windows.It's too cold.

1.rang (主句过去进行时,when从句用过去时,表示"在铃声响起的时候,你在干什么?")
2.close(祈使句,所以用动词的原型)