问题补充:
The young lady was careful .
A. not repeating her mistake
B. not repeated her mistake
C. to not repeat her mistake
D. never to repeat her mistake
答案:
A. not repeating her mistake
B. not repeated her mistake
C. to not repeat her mistake
(答案→)D. never to repeat her mistake
解析:这是短语be careful not to do sth.的搭配,故选D。