tight (adj.)
紧绷的

例句：
Those pants are too tight--you should try on a bigger pair.
这条裤子太紧绷了, 你应该试大号一点的。

blow out
聚会、爆炸

例句：
We arrived two hours late at the big blow out for Charle's birthday because our car had a blow-out.
由于我们车胎炸了，所以我们晚了两个小时到达查理举行生日宴会的地方。
（这句话里第一个blow-out是指规模很大的聚会，第二个blow-out是指汽车的轮胎炸了。）

I don't know for sure.
我不能肯定。

对话：
A: Is that the bus to the railway station? 
B: I don't know for sure. You'll have to find out yourself.