1，小明和小红自学中文。

Xiao Ming and Xiao Hong learn Chinese all by themselves

2，你必须先完成你的作业。

You must finish your homework first

3，我稍后给你回电话。

I will call you back later

4，在小红的帮助下我完成了作业。

With the help of Xiao Hong, I finished my homework