It was not until he became very ill he went to see a doctor.A. whatB. thatC. whenD. then

问题补充：

It was not until he became very ill he went to see a doctor.

A. what

B. that

C. when

D. then

答案：

A. what

(答案→)B. that

C. when

D. then

解析：考查含有not until的强调句型。It is + not until +其它+that,句意：直到他生病了他才去看医生。故选B。