a)并列与递进关系: and, or, also,neither…nor…,either…or…, similarly, equally, in the same way, that is to say ,as well as, the same …as,besides, additionally, furthermore, moreover, in addition to ,what is more
b)因果关系:because, for, since, as, thus, hence, therefore, so, so…that, consequently, accordingly, due to, thanks to, as a result ,because of ,in that, for this reason, of course