I'm On your side.

我全力支持你。

He won an election.

他在选举中获胜。

How could she possibly ace it when she keeps cutting class all the time?

她老是缺课，怎么能考100分？

She is a composer for the harp.

她是位写竖琴曲的作曲家

Once you begin，you must continue.

一旦开始，你就得继续。

I don't know how to express my gratitude.

我不知道怎样来表达我的感激之情。