Question

should 后面是不是必须跟动词原形?比如:

Answer 1

First

adv.

首先

First we'll have breakfast,then we'll walk to school.

我们首先吃早饭,然后步行去学校.

第一次,初次

when we first met

我们初次见面时

Firstly

adv.

首先；第一

There are three reasons against it:First...

有三个反对的理由

两个都对的,词性不同而已!