1·They are not afraid to tackle the issues or let the sparks fly when necessary.
他们不怕应付这些问题, 必要时也不惜进行唇枪舌剑的激烈争论。
—— 《柯林斯英汉双解大词典》
2·With any container that you choose, you need to ensure that it allows the water in it to drain when necessary.
对于您选择的任何容器，您需要确保在需要的时候它能够排除里面的水。
3·A new system allows a combine harvester, say, to send a call over to a tractor-trailer so the driver can unload the grain as and when necessary.
例如，一种新的系统允许联合收割机向牵引拖车发送呼叫，以便司机可以在必要的时候卸载谷物。
4·The government, when necessary, has recourse to the armed forces.
政府在必要时可以动用军队。
—— 《牛津词典》
5·When necessary, instinct is the most reliable resource you can fall back on.
必要时，本能是你可使用的最可靠的资源。
—— 《柯林斯英汉双解大词典》
6·Sometimes I watched the online classes again when necessary.
有时候，我会在必要时再看一遍在线课程。
7·Although they are big animals, elephants can move silently when necessary.
虽然大象是大型动物，但在必要时它们可以悄悄地移动。
8·Only flush the toilet when necessary: this means to not use the toilet as a garbage to avoid wasting water.
只在必要时冲厕所：这意味着不要把厕所当作垃圾桶使用以避免浪费水。
9·We create an opportunity for assessment and intervention, to help clients and communities cope effectively with their reality and change that reality when necessary.
我们为评估和干预创造机会，帮助客户和各大团体有效地应对现实问题，并在必要时对现实做出改变。
10·They generally tend to share very similar tastes in music and clothes, they spend their money in having a good time, and save for holidays or longer-term plans when necessary.
他们通常倾向于在音乐和服装上有着非常相似的品味，他们把钱花在享乐上，并在必要时为假期或长期计划存钱。