9.for sure确定地；肯定地；毫无疑问
We don't know what happened for sure.我们说不准发生了什么事情。
One thing's for sure, his vocal style hasn't changed much.有一点是肯定的, 他的歌唱风格没有什么大改变。
I don't know for sure.我不太肯定。
10.to make sure (that) …
(ensure)设法确保…
Make sure that you follow the instructions carefully.确保认真按照说明书操作。
(check)查明…；核实…；弄清楚…
I'm going to make sure the door's locked.我要去看看门是否已经锁上。
We watched the baby to make sure that she was asleep.我们看了看婴儿, 看她是否已经睡着。