certainly 
英 [ˈsɜːtənlɪ]  美 [ˈsɜrtənli] 
adv. 无疑，当然，必定

例句：
Whatever it is, it certainly seems to work. 

无论它是什么，看上去它肯定是起了作用。

If nothing is done there will certainly be an economic crisis. 

如果不采取措施，就必将发生经济危机。

The public is certainly getting tired of hearing about it. 

公众绝对听腻了此事。

Certainly, pets can help children develop friendship skills. 

毫无疑问，宠物能帮助孩子们掌握交友技巧。

Could you give me a lift?—Certainly. 

能搭你的车吗？——行。