Whether you believe it or not, it is ________ that causes your illness．
A.because of your being overweight
B.your being overweight
C.because you are overweight
D.you are so overweight
网友回答
B解析这是一个强调结构，对原句中的主语your being overweight进行强调。because 引导的从句和because of短语不能作主语。