问题
选择题
―Look! What a mistake! Why?
―Sorry, I _________ on it.
A．don’t concentrate
B．hadn’t concentrated
C．haven’t been concentrating
D．wasn’t concentrating
答案
答案：D
搜题请搜索小程序“爱下问搜题”
―Look! What a mistake! Why?
―Sorry, I _________ on it.
A．don’t concentrate
B．hadn’t concentrated
C．haven’t been concentrating
D．wasn’t concentrating
答案：D