The two writers worked well in combination.两位作家合作得很好。
An alloy is a combination of two or more different metals.合金是两种以上不同金属结合而成的。
You cannot open the safe unless you know the combination.不知道号码组合是打不开这个保险柜的。
The three possible combinations of two letters chosen from ABC are AB,BC and AC.从ABC中抽出两个字母可组成AB、BC和AC三种组合。