I ___ out when the phone ranghappenhappenedhappened tohappened to he

问题描述:

I ___ out when the phone rang
happen
happened
happened to
happened to he

happened to be

happened
记住when的两边通常是对应的,
因为ring用过去时rang,所以happen也用过去时happened

happened to he
这里的be 和后面out 构成“在外面”的意思
happen to do 是“恰好在做某事”的意思

happened to he