高考加油用英语可以说以下几种：

Good luck on your exams!

Good luck for your exam and do your best.

You can do this. Best of luck.

Go for it, you've got this!

Hang in there, you're almost there!

No problem, you can do it!

Fighting!

这些表达都可以用来为高考加油鼓劲，希望这些信息对你有所帮助。