(1) in case that意为“万一，以防，如果”，指为了安全等目的事先做某事以做防范，防止(不好的事发生)，或为了对以后可能出的情况做好准备。
- You should insure your house in case there's a fire.
你应为你的房子投保，以防发生火灾。 - You should telephone 999 if there's a fire.
如果发生火灾，你应拨打999。
＊上面两句中所说事项发生的次序是不同的。第一句是说在火灾可能发生前对房子投保；第二句是说在发生火灾时打电话(给消防部门)。这里in case表示防备万一；if表示已有某种结果/后果。
- Take John's address with you, in case (that) you have time to see him when you're in London.
把约翰的地址带上，万一你在伦敦时有时间可以去看他。 - In case I forget, please remind me of my promise.
万一我忘了，请提醒一下我许过的诺言。
(2) ①in case of较in case意思要宽，可用于与if相同的场合，意为“万一，如果”。
- In case of fire, ring the alarm bell. (=If there is a fire...)
万一发生火灾，拉响警钟。 - In case of rain, the meeting will be put off.
万一下雨，会议将推迟。
②用in case的句子中，常要用should，特别是在书面语中；口语中常用直陈语气。
| { | 万一下雨，运动会将推迟。
The sports meet will be postponed, in case it rains. (口语) The sports meet will be postponed, in case it should rain.(书面语) |
＊但也有人认为用should比不用should表示发生的可能性更小。
- I'll get some beer in case Aunt Mary comes. (She may come.)
我将弄些啤酒来，万一玛丽姨妈过来。
③在表示过去情况时，in case之后往往用should，特别是在书面语中。口语中常不用。
- I packed a swimsuit in case I should have time to go to the beach.
我将游泳衣装入行李，以备我有时间去海滩时用。 - He took an umbrella with him in case it should rain/it rained.
他带上一把雨伞，以防下雨。
④in case后面也可不接句子，意为“以防万一”。
- It may rain — you'd better take an umbrella with you (just) in case .
可能要下雨，你最好带上雨伞以防万一。 - The bus is usually on time, but start early, just in case .
公共汽车通常是准时的，不过还是早点动身，以防万一。
(3) in the case of意为“对于……来说；就……的情况而言”，相当于“as far as...is/are/was/were concerned”。
- Poverty depresses most people; but in the case of my father, it only made him work harder.
贫穷使大多数人消沉。但就我父亲来说，却只会使他更加努力。 - It's the kind of story we think of as myth. But in the case of Lincoln, it's true.
这是我们通常认为是神话的故事，但就林肯来说，这却是真实的。
(4) ①in the event (that)可以表示“如果”，与用if 和in case(作“如果”解时)意思相同。
- In the event that our team wins, we'll hold a big party.
如果我们队赢了，我们将召开一个大型庆祝会。
②in the event还作“实际情况是……”解，常与but连用，后接句子。
- We had grave doubts about the wisdom of the plan in private at the time, but in the event it proved to be most advantageous to us.
当时，我们在私下里对该计划的明智性提出了严重怀疑，但实际情况证明它对我们极为有益。
(5) in the event of意为“如果发生(某情况)，万一”，与in case of意思相同。
- In the event of her being sick, she will lose her opportunity to go abroad.
万一她病了，她将失去出国的机会。 - In the event (In case) of rain the ceremony will be held indoors.
万一下雨，仪式将在室内举行。
