To such an extent _________ his empty speech that some of us beg

To such an extent _________ his empty speech that some of us began to doze.
A、did he go on with
B、he would go on with
C、he went on with
D、he did go on with
【正确答案】：A
【题目解析】：句意：他的演讲空洞到这种程度以致于我们都开始打瞌睡了一个倒装句,did 作强调