dip
dip sth into sth
dip sth in
蘸；浸
He dipped the brush into the paint.
他拿畫筆蘸了蘸顏料。
Dip your hand in to see how hot the water is.
把手伸進去看看水有多熱。

reason
reason why...
reason that...
reason for sth
reason for doing sth
原因；理由；解釋
I'd like to know the reason why you're so late.
我想知道你為什么遲到那么長時間。
We aren't going for the simple reason that we can't afford it.
我們不去,只是因為我們負擔不起。

smart
聰明的；機敏的；精明的
She's smarter than her brother.
她比她哥哥聰明。
That was a smart career move.
那是個人事業發展上的一著妙棋。
OK, I admit it was not the smartest thing I ever did (= it was a stupid thing to do).
好吧,我承認那件事我辦得很不漂亮。

來源:可可英語 http://www.ccdyzl.cn/video/201709/526021.shtml