pm——post meridiem，中午之后。

pm7:30指的是19:30，晚上。

7:30英语有两种说法：half past seven和seven thirty.

例句：

We get to school at half past seven day.

我们每天七点半到校。

It's half past seven. it's time you went to work.

7点半了。你该去上班了。