It was ___his mother came in ___to prepare his lesson.
It was ___his mother came in ___to prepare his lesson.
A.not until ;did thhe boy begin
B.until;that the boy began
C.until;did the boy begin
D.not until;that the boy bigan
问题补充:
有强调有倒装,应该选哪一项呢?有人人为D项没有半倒装,应改选B