问题
选择题
If they what I was saying, they'd know what I was talking about
A．took the trouble to listen to
B．had trouble listening to
C．take the trouble to listen to
D．have trouble listening to
答案
答案：A
题目分析：考查时态和虚拟语气：句意：如果他们不怕麻烦听我说的话，他们就会知道我说的是什么了。take the trouble to不怕麻烦去做；have trouble （in） doing是“做…有困难”，所以排除BD，而且主句是would do是虚拟语气，从句用过去时表示虚拟，选A。
）与甲醛、氯化氢以物质的量之比1:1:1反应，可获得一种杀虫剂中间体X和H2O。