be sure of

基本解釋

We have to be sure of that first.
我們得確信這是第一位的。
“You can be sure of one thing: I’m leaving,” he says, adding that he has no plans to run for election in 2014.
“有一件事是肯定的：我要離開了，”他說道，同時還表示他并沒有計劃參加2014年的競選。
All they can be sure of is that colleges will accept or reject them, and it's like being accepted or rejected for a date—only much more intense, and their parents know all the details.
他們惟一確信的，就是大學(xué)可能接受也可能拒絕他們，就像約會可能被接受或拒絕一樣——只不過前者更嚴(yán)重一些，而且父母會知道有關(guān)的一切細節(jié)。
blog.sina.com.cn

He could not be sure of their support if he declared that the purpose of the war was to free the slaves.
So, he started asking himself the question, "What can I be sure of?"
他首先問自己一個問題,"我究竟能夠確信什么呢"
耶魯公開課 - 心理學(xué)導(dǎo)論課程節(jié)選
But I'm sure you can easily see how these styrofoam balls could, in fact, be a mono layer of gold nuclei.
這個實驗怎么工作的,我們先來做些計算，但我相信你們都已經(jīng)。
麻省理工公開課 - 化學(xué)原理課程節(jié)選

Although now plainly well placed to win the presidency, the Colonel cannot be sure of it.
ECONOMIST: The colonel rides on