—David. It's good to meet you. ______—Three years, but I'm thinking about stopping soon.—Why's that?—It's time for a change, and I can't work the long hours any more.

A、 When did you come to the United States?
B、 What time do you get to work every day?
C、 How many hours have you worked so far today?
D、 How long have you been a teacher in New York?

【正确答案】 D

【答案解析】解析：对话中David的回答是“三年”，是一个时间段，由此可知提问者问的是时间长度，并根据最后的回答可知问题与工作有关。D项问的是“你在纽约当老师多久了?”，最符合情景。