because与because of
1.because是连词，后面接从句，作原因状语从句，通常不与so连用。例如：
(1)I do it because I like it.我做这件事是因为我喜欢。
(2)We didn’t enjoy the day because the weather was so awful.因为天气太糟糕了，我们玩得不愉快。
(3)He didn’t attend the meeting because he had too much work to do.他因为要干的活儿太多，没来参加会议。
2.而because of是介词短语，在句中一般用作状语，可置于句首和句末，后面接名词、代词及名词性短语。常用来表示引起事件发生的直接原因。例如：
(1)I had to move because of my job.因为工作的原因我得搬家。
(2)Because of illness, the boy did not go to school.因为生病，这个男孩没有去上学。
(3)They had to stay at home because of a heavy rain.因为一场大雨，他们只好呆在家里。
(4)The boy was late for school because of the heavy traffic.由于堵车，这个孩子上学迟到了。
3.because of 和because的意思都是“因为”，区别在前者跟短语，后者跟从句。例如：
(1)They didn’t go to the museum because of therain.他们因为下雨没去博物馆。
(2)They didn’t go to the museum because itrained.他们因为下雨没去博物馆。