Because引导的原因状语从句有时可与because of 短语转换,because of后加的原因可以为好或坏
但最正规的还是because
He can’t come because he is ill. / He can’t come because of his illness.
他因病不能来。
I said nothing about it because his wife was there. / I said nothing about it because of his wife’s being there.
因为他妻子在那儿,我对此事只字未提。