1. 表示并列、递进或顺承关系的并列连词：and, both... and..., neither... nor..., not only... but also..., as well as
Not only can a beautiful smile make ourselves happy, but also it enables others to feel delighted.
一个灿烂的笑容不仅能使我们自己高兴，而且能使他人感到愉快。
2. 表示转折的并列连词：but, yet；表示对比关系的并列连词：while
I was never very neat，while my roommate Kate was extremely organised.
我从来不是一个很爱整洁的人，而我的室友凯特却极有条理。
