【题目】 I wonder what makes him a good English teacher.
He ________ as a volunteer in the UK for two years, which helps him with his work a lot.
A. has served B. serves C. had served D. served
在线课程【答案】D
【解析】
考查时态。句意：——我不知道是什么使他成为一个好的英语老师。——他在英国做了两年的志愿者，这对他的工作帮助很大。这里指在过去某段时间内发生过的事，在陈述一件过去的事实，所以用一般过去时态，故答案为D。