避孕套如果谨慎使用，是一种有效的节育方法。

Condoms are an effective method of birth control if used with care.

《柯林斯英汉双解大词典》

老师警告说，如果他们上课时继续使用手机就予以没收。

The teacher threatened to confiscate their phones if they kept using them in class.

《牛津词典》

如果你工作时要使用油漆，戴上防毒面具会是明智之举。

It's smart to use a respirator if you're working with paint.

《柯林斯英汉双解大词典》

If it was an unordered list, we were basically stuck with linear search. Got to walk through the whole list to see if the thing is there.

如果是一个未排序的列表,基本上我们就只能使用线性搜索了,通过遍历整个列表来查看。

麻省理工公开课 - 计算机科学及编程导论课程节选

If it's possible, use animals that don't feel pain, or use lower forms of life.

如果可以的话，请使用那些感觉不到疼痛的动物，或者用低级生物。

需要动物实验吗？ - SpeakingMax英语口语达人

If we weren't so pressed for time, I kinda wanna see how long we could get away with this before it gets awkward, but that, in fact, is an infinite loop t hat's hopefully deliberate.

如果有时间，我想看看,我们需要花多长时间解决这一问题，事实上，它是我故意,使用的无穷循环。

哈佛公开课 - 计算机科学课程节选