这把她的魂都吓飞了，如果你一定要知道的话。而且我也被吓坏了。

It scared the hell out of her, if you must know. And me, too.

《柯林斯英汉双解大词典》

如果你一定要抽烟，请选择吸烟区第一排的座位。

If you must have a cigarette, choose a seat in the first row of the smoking section.

youdao

如果你一定要油炸，一定要把食物放在厨房的纸上，翻动几次尽量把油吸干。

If you must deep fry, be sure to drain the food on kitchen paper, turning it a few times to drain off as much oil as possible.

youdao

So, if you want to go at 1:00, you're welcome to do so, but please arrange it with my assistants.

如果你想去上1点的课，也可以，但是一定要和我的助教安排一下。

麻省理工公开课 - 固态化学导论课程节选

So if you want people to get an education, maybe some sort of subsidy is appropriate.

所以如果你想要人们受教育，也许一定形式的补助是合适的。

对于奖学金制度 - SpeakingMax英语口语达人

Any of you who have access to a four- or five-year-old, a sibling or something-- Do not take one without permission, but if you have access to a four- or five-year-old you can do this yourself.

如果你身边有四五岁大的孩子,兄弟姐妹什么的,一定要先得到同意再去试验,如果你身边有四五岁大的孩子,你可以自己去试试

耶鲁公开课 - 心理学导论课程节选