如果必要的话，病人可向自己的医生咨询以得到更多的建议。

If necessary the patient can then visit his doctor for further advice.

《柯林斯英汉双解大词典》

确保你的鞋子是干净的，如果必要的擦得光亮光亮。

Make sure your shoes are clean and polished if necessary.

youdao

可以直接“跳到”一个合适的级别(有时甚至建议这样做)，如果必要的先决条件具备的话。

It is possible and sometimes advisable to "jump" to an appropriate level; should the necessary pre-requisites be in place.

youdao

Again, we reserve the right to move people around if we have to, just to balance load, but we want you to find something that fits your schedule rather than ours.

再说一遍，如果必要的话,我们保留转移你们的权利，只是为了平衡每节课的人数，但是我们希望你们能找到,比适合我们更适合你们时间安排的课时。

麻省理工公开课 - 计算机科学及编程导论课程节选

And sometimes had them killed if he had to if he thought that's what he should do, because there wasn't any sort of challenge to his authority.

如果有必要,他甚至会杀掉那些碍事的议员,因为没有什么可以挑战他的权威

耶鲁公开课 - 欧洲文明课程节选

Really there's no work to be done if I am handed all in sorted order so, you know, There's no work to be done if I'm handed all of the arrays in sorted order so, you know, if I demand that you give me this assumption that the cups are already sorted and then I'll sort them for you, I mean, this is kind of a cyclical argument.

如果杯子是有序排列的,那就没必要再对它进行排序了，同样如果给出的序列本身就是有序的,那也不必再做什么，如果给出这样的假设：,杯子已经有序，但仍需要对其进行排序，这像是个循环的论点。

哈佛公开课 - 计算机科学课程节选