Simon thought his computer was broken _______ his little brother pointed out that he had forgotten t

Simon thought his computer was broken _______ his little brother pointed out that he had forgotten to turn it on

A.until

B.since

C.after

D.because

答案及解析: A

解析:

本题考查连词。根据句意他一直以为电脑坏了,直到他弟弟告诉他忘记开机了;

not...until...意为“直到……才”。