gain admittance

For a moment I considered it absurd that I should need such a weapon to gain admittance into my own residence.

当时我认为需要这么一个武器才能进自己的家，那是荒谬的。

So, how then was he to gain admittance?

那么他怎样才能获准进入呢？

as the theater was full , we were unable to gain admittance

由于电影院客满，我们没能获得入场许可。

a secret word or phrase that one uses to gain admittance or access to information

口令，暗号某人用来得以进入或获得信息所使用的秘密的单词或短语