【题目】Simon thought his computer was broken ________ his little brother pointed out that he had forgotten to turn it on.
A.until
B.because
C.while
D.though

【答案】A
【解析】句意：Simon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”。故选A。