―Look! What a mistake! Why? ―Sorry, I __
题型:选择题
问题:
―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
―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