The Quick Answer
Cannot (one word) is the most common expansion of the contraction can't.
cannot(一個單詞)是縮寫can't的展開形式。
Can't can also be expanded to can not (i.e., two words), but this is less common and usually reserved for emphasis.
Can't也可以展開為can not(兩個單詞)，但是這種寫法比較少見，有時只是為了強調。
For example:
I cannot do it!
(Can't is usually expanded to cannot.)
Can't通常展開為cannot
I can not do it!
(This is considered more emphatic.)
這樣更具有強調性
Of course, the words can and not sometimes appear alongside each other when the not forms part of another construction (such as not only).
當然，can和not有時也只是因為各自的搭配而碰巧挨到一起。
For example:
Kevin can not onlyrap but dance too.
凱文不僅能饒舌也能跳舞。
(Here, can not must be written as two words. It is not an expansion of can't.)
在這裡，can not必須寫成兩個詞，並不是can't的展開形式。
Cannot or Can Not?
Cannot and can not are interchangeable as expansions of the contraction can't.
cannot和can not在作為can't的展開形式時，是可以互相取代的。
However, the modern preference is to use cannot. Of note, many spellcheckers even highlight can not as an error.
然而在現代，人們更傾向於使用cannot。值得注意的是，許多拼寫檢查軟體甚至高亮顯示can not作為錯誤的拼寫。
Cannot和Can Not的例子
Here are some famous quotes featuring cannot and can not.
這裡有一些包含cannot和can not的名言供你參考
You cannotescape the responsibility of tomorrow by evading it today.
今天你迴避了責任，明天它依舊存在。
-Abraham Lincoln 亞伯拉罕·林肯(第十六任美國總統)
There cannotbe a crisis next week. My schedule is already full.
下周不可能有危機，我的日程早就排滿了。
-Henry A. Kissinger 亨利·基辛格
Conflict can not survive without your participation.
沒有你們的參與，衝突就無法產生。
-Wayne Dyer 韋恩·戴爾
(We have marked this wrong because can not is not the modern convention.我們把這個標記為錯誤用法，是因為can not不是現代習慣用法。)
A flower cannotblossom without sunshine, and man cannot live without love.
花兒沒有陽光不能綻放，人沒有愛不能生存。
-Max Muller 麥克斯·穆勒
Three things cannotbe long hidden: the sun, the moon, and the truth.
有三個東西是無法被長久隱藏的：太陽，月亮，以及真理。
Can Not 用於強調
You should use can not over cannot when the not is emphasized.
只有當not被用於強調時，你才需要考慮用can not而不是cannot
For example:
I can nottolerate laziness!
我不能容忍懶惰
The two-word version makes it clearer that the word not should be emphasized. This is most useful in an exclamatory sentence, i.e., one that ends in an exclamation mark.
用兩個單詞的寫法來使not的強調意思更加清晰明了。通常用在感嘆句中，也就是結尾有感嘆號的句子。
必須用Can Not的時候
It is possible to see can and not as two separate words, especially with the correlative conjunction not only...but also.
將can和not作為兩個單獨的單詞來使用時是可以出現can not的形式的，尤其是注意關聯詞not only...but also裡這個not。
Danielle can not onlycook but also bake.
丹妮爾不僅會做飯，而且會烤麵包。
My dog can not onlyroll over but also play dead.
我的狗不僅會翻身，還會裝死。
In these examples, cannot is not an option.
在這樣的句子中，cannot是不能用的。
看到這裡，
你都明白了嗎？