because of 是復合介詞，其後接名詞、代詞、動名詞、what 從句等。
如：I didn’t buy it because it was too expensive. 我沒有買是因為它太貴了。
He is here because of you (that). 他為妳<(那事)而來這裏。
He lost his job because of his age. 由於年齡關系他失去了工作。
We said nothing about it, because of his wife’s being there. 因為他妻子在那兒，我們對此只字未提。
He knew she was crying because of what he had said. 他知道她哭是因為他說的話。
註：
because of 之後可接what 從句，但不能接that 從句或沒有引導詞的句子。
如：他因病未來。誤：He didn’t come because of he was ill.
He didn’t come because of he was-font-family: 'Times New Roman'">
誤：He didn’t come because of that he was ill. 正：He didn’t come because he was ill.
正：He didn’t come because of his illness.
比較以下同義句：
他離開了這家公司，是因為老板在會上講的話。
正：He left the coar-indent-count: 2.0">
正：He left the company because of the thing that the boss said at the meeting.
我不能因為有個家就停止鬥爭。
正：I can’t stop fighting because I have a family.
正：I can’t stop fighting because of having a family.2. beca 20pt; mso-char-indent-count: use
所引導的從句除用作原因狀語外，還可用作表語。如：
It is because he loves you. 那是因為他愛妳。
而復合介詞because of 所引導的介詞短語通常用作狀語而不用作表語。如：他因雨缺席。
誤：His absence was because of the rain.
正：His absence was due to the rain.
正：He was absent because of the rain.
但是有時若主語是代詞(不是名詞)，也可以用because of
引出的短語作表語。如：引出的短語作表語。如：
It is just because of money. 那只是因為錢
because和because of的意思都是：因為，由於。但是在用法上又有不同。
because：後加從句。
比如：She doesn't go to school because she is ill.
她沒來上學因為她生病了。在這句話中。she is ill就是從句。所以because後面就是接從句。
而再來看because of。because of：後加代詞/名詞/動詞的ing形式。
還是拿剛才那句話來比較。用
because of
來代替後。就是：
She doesn't go to school because of her illness. 同樣的壹個意思。接連的卻不同。
her illness是名詞。這就可以說明。because of後接代詞/名詞/動詞的ing形式。