Not until his mother came in to prepare his lessons.
A. did the boy begin
B. the boy began
C. began the boy
D. the boy did begin
网友回答
(答案→)A. did the boy begin
B. the boy began
C. began the boy
D. the boy did begin
解析：not until 位于句首，句子使用部分倒装。C答案为完全倒装。