In case” and “if”
“In case” 和“if”

Consider this sentence:
看一下下面的句子：

In case it rains I will take an umbrella.
以防下雨，我要帶把雨傘。

This means : Because there is a possibility that it will rain later, I will take an umbrella now.
這句話的意思是：因為一會兒有下雨的可能，我現(xiàn)在要帶把雨傘。

“In case…” is an idiomatic phrase that we use when we talk about taking precautions.
“In case”為習(xí)語性詞組，通常在要采取預(yù)防措施的情況下使用。

It is used mainly in informal speaking and writing.
主要用于非正式口語和寫作中。

“Just in case…” is a version of the phrase commonly used in spoken language:
“just in case(以防萬一)”是這個詞組的變形，通常用于口語當(dāng)中。

“I’ll pack an extra shirt, just in case.”
“我還是再裝件襯衫吧，以防萬一?！?/div>

“In case…” DOES NOT mean “if…”
“In case” 不等于“if”

Now consider this sentence:
現(xiàn)在看一下下面的句子：

If it rains I will take an umbrella.
如果下雨，我就帶把雨傘。

This means the following: If it is raining at the moment I leave the house, I will take an umbrella, but if it is not raining, I won’t.
這句話的意思是：如果我離開家的時候下雨，我就帶把雨傘，但如果不下雨，我就不帶了。

In the case that it rains I will take an umbrella.
如果下雨，我就帶把雨傘。

means the same thing.
這句話的意思和上面是一樣的。

“If …” = “In the case that…” / “in the event that…”
“If” 等于“In the case that”或者“in the event that”

Compare the following sentences:
對比下面的句子：

In case my house is burgled I’ll take out insurance.
=> as a precaution BEFORE it is burgled
以防家里被盜，我要買一份保險。
=> 作為一種預(yù)防，發(fā)生在被盜之前。

If my house is burgled I’ll take out insurance.
=> AFTER it has been burgled? That’s too late!
如果我的家被盜，我要買一份保險。
=> 發(fā)生在被盜之后？太晚了吧！

In case I crash the car I’ll wear a seatbelt.
=> as a precaution BEFORE I have a crash
為了防止撞車，我要要系上安全帶。
=> 作為一種預(yù)防，發(fā)生在撞車之前。

If I crash the car I’ll wear a seatbelt.
=> AFTER you have crashed? That’s too late!
如果我撞車了，我會系上安全帶。
=> 發(fā)生在自己撞車之后？太晚了！

“In the case of…”
“In the case of” 就...而言

“In the case of…” means “as regards” / “with regard to” / “as far as … is concerned” etc. For example:
“In the case of”等于 “as regards (至于)”/ “with regard to（就...而言）”/ “as far as...is concerned ( 據(jù)...考慮)”等等，例如：

In the case of the Property, the lease agreement has been executed for a period of ten years.
至于所有權(quán)的問題，該借貸協(xié)議已經(jīng)執(zhí)行了10年。

(As regards the Property…)
(至于所有權(quán)問題......)

“In the case of…” can also mean “for”, as in this example:
“In the case of…” 也可以表示“for(因為)”例如：

The authority may impose a fine in the case of non-compliance with the regulations.
如果企業(yè)違反該條例，政府可以進(jìn)行罰款。

(…for non-compliance)
(......因為違反......)

“In case of…” (without “the”)
“In case of... ”(沒有“the”)

“In case of…” (without “the”) means “in the case that” / “if”. It is used exclusively in formal notices and announcements.
“In case of...”(沒有 the)指的是“in the case that (如果)”/ “if (如果)”。該詞只在正式的通知和宣告中。

For example:
例如：

In case of fire do not use the lift.
如果發(fā)生火災(zāi)，不要使用電梯。

(If there is a fire…)
(如果發(fā)生火災(zāi)......)

In case of rain the wedding reception will be held in the hotel ballroom.
如果下雨，婚禮接待就在酒店的舞廳舉行。

(If it rains…)
(如果下雨......)

“In case of…” (without “the”) SHOULD NOT be used except in formal notices and announcements.
“In case of ...”(沒有 the)僅用于正式的通知和宣告中。