一日一句【54】because of和because

because of和because

示例：
The flight was cancelled because of the snow storm.
由于有暴风雪，这航班取消了。

because是连接词，它引导一个从句，从句中有主语，有动词。because of是介词。它后面跟名词、名词词组或代词作为介词宾语。两句的含意基本相同。

Mary stayed home yesterday because she had a headache.
Mary stayed home yesterday because of her headache.
玛丽昨天因头痛而在家休息。

John got home later because the traffic was heavy.
John got home later because of the heavy traffic.
因为交通堵塞，约翰回到家已很晚了。

It is difficult to understand his theory because it is complex.
It is difficult to understand his theory because of its complexity.
他的理论很复杂，难以明白。