跟他说话没用——他就是不听。

It ___was ___no ___use ___talking to him - he just wouldn't listen.

在那家酒吧里试图抽烟是没用的。

It ___was ___no ___use ___trying to smoke cigarettes in that pub.

担心你无法改变的事情是没用的。

It ___is ___no ___use ___worrying about things you cannot change.