whereas与while的区别

从属连词whereas意为：“然而，但是，反之”（but, in constrast ,on the contrary, while）用于陈述相反的话，引出表示对比、对立或直接相反（Direct Opposition）的状语从句，是正式用法，语气强并且书卷气较重，通常多位于居中，也可置于句首；通常多用逗号隔开，也有语法学家和某些权威词典主张不用逗号。如（3）His parents were rich, whereas mine had to struggle.（4）Many small birds use new sites for each nesting, whereas large birds often reuse the same nest.（5）Whereas it is day with us, it is night with the Americans. (=It is day with us, whereas it is night with the Americans.)应该注意的是whereas引导的从句与主句在意义上不仅是对立和相反的，而且也是并列的（因此也有人认为whereas是并列连词），两者可以互换，无论主句在前，还是从句在前，其句意都不变。如（6）Old people in my country usually live with their children, whereas the old in the United States