【题目】As we all know, it was _________ that resulted in the terrible car accident.
A. because of her carelessness
B. because she was careless
C. her being careless
D. she was so careless
在线课程【答案】C
【解析】本题可采用减元法，把强调句型中的It was…that…去掉，就不难看出该句缺少主语。Her being careless是-ing形式复合结构，在句中充当主语。故选B。