一、词性不同
1、because是连词,意思是:因为;由于。
2、because of是复合介词,意思是:因为,由于(说明)。
二、用法不同
1、because可用来引导让步状语从句,这时,通常用于否定句或疑问句中。还可引导表语从句。
2、because of其后可接名词、代词、动名词或由what引导的从句(但不是直接接从句)。当主语是代词时,because of短语在句中可用作表语。
He came back late because there was something wrong with his car.
他回来晚了,因为汽车出了故障。
I did not go to the cinema because of the intense cold.
我因为严寒没出去看电影。
He is here because of you(that).
他为你(那事)而来这里。
Please be brief because I am in a hurry.
我有急事,请长话短说。
I didn't buy it because it was too expensive.
我没有买是因为它太贵了。