can; can’t; should; shouldn’t; must; may后一定加動(dòng)詞原形。

　　如：The girl can’t swim, but he can skate.

　　女孩不會(huì)游泳，但是會(huì)滑冰

　　Don’t talk in class, you should listen to the teacher carefully.

　　不要再課上說(shuō)話，你應(yīng)該認(rèn)真聽(tīng)老師講。