1. because (conj.) / because of (prep.)
最常見的「因為」就是because了，關於because有以下幾點要注意:
1. because 是從屬「連接詞」，因此後面要加上一個完整句子，也就是和一般句子一樣必須包含有主詞、動詞。常見同義字有since, as，兩者也都是連接詞。
2. because 加上了 of 之後變成了「介詞」，因此後面不再連接一個完整的句子，而是必須要加上名詞或是動名詞。
He got a good grade because/ since he (主詞) studied (動詞) hard yesterday.
他得到了一個很好的成績，因為他昨天很用功念書。
Tom cannot go to work because of sickness. (名詞)
因為生病，湯姆不能去工作。
2. due to (prep.)
due to 是個「介詞」，因此必須要加上名詞，後面不可以連接一個句子。
Anna’s coming to school late was due to the rain (名詞). (O)
Anna’s coming to school late was due to it was raining outside. (X)
安娜上學遲到是因為下雨的緣故。
在我們進入比較之前，可以先看看以下這部影片掌握大致的觀念:
Due to or because of?
3. because of 和 due to 到底哪裡不一樣？
綜合上述，because of 和 due to 兩者雖然都是介詞，但是他們的用法卻有很明顯的差異，因此是不可以隨便替換的！
因此想要分辨兩者的用法，首先得先確認「主句的動詞」:
1. 當句子的主動詞不是 be動詞，而是一般常見的普通動詞時，我們要使用 because of，此時 because of 還可以用 on account of 或 in view of 來替換。此時，because of在語意上適用來修飾「動詞」的。
Robert cannot go to party because of his work. (O)
(羅伯特因為工作不能參加派對) － 主動詞為普通動詞 go。
= Robert cannot go to party on account of / in view of his work.
此時，Because of 是用來修飾前面的動詞 go to the party，解釋羅伯特不能參加派對的原因。
Robert cannot go to party due to his work. (X)
此時使用due to在語法上是錯誤的，原因如下:
2. 當句子的主動詞為am, is, are, was, were 等「be 動詞」時，我們要用due to，因為due to 僅用於be 動詞之後做形容詞片語，簡單來說是用來說明、形容「名詞」的。此時 due to 等同於 caused by, resulting from。例如：
The serious accident was due to his careless driving. (O)
(這起嚴重意外事故是由於他駕駛疏忽所造成) － 動詞為be 動詞: was。
= The serious accident was caused by his careless driving.
此時，due to 是用來修飾前面的名詞 accident，解釋說明意外發生的原因。
The serious accident was because of his careless driving. (X)
[實戰練習] 考考你
The crisis was ˍˍˍˍˍˍˍˍˍˍˍˍ the spread of the disease.
The crisis took place ˍˍˍˍˍˍˍˍˍˍˍˍ the disease.
The concert has been cancelled ˍˍˍˍˍˍˍˍˍˍˍˍ lack of interest.
ˍˍˍˍˍˍˍˍˍˍˍˍ we』ve got a few minutes to wait for the train, let’s have a cup of coffee.
She began to grow nervous, ˍˍˍˍˍˍˍˍˍˍˍˍ he had promised to meet her at dawn.
4. Owing to
另一個常用的同義詞owing to 看起來和due to 很像，雖然都是以介詞to 做結尾，但千萬要注意，Owing to跟的用法due to不同，而是跟because of 一樣，和普通動詞連用。
Example:
They decide to cancel the flight, owing to the storm.
= Owing to the storm, they decide to cancel the flight.
owing to常見置於句首。
= They decide to cancel the flight because of the storm.
由於暴風雪的緣故，他們決定取消這班飛機。
5. Since(conj)
since 的意思比起表達原因的因為，更適合翻譯成「既然」
Since it is so hot, let’s go swimming. 既然天氣這麼熱，我們去遊泳吧。
6. As (conj)
As的意思上跟because相同，但要注意的是在句子中，as比較強調的結果的部分；because則比較強調原因；理由(reason)。
I hope they』ve decide to come as I wanted to hear about their India trip.
(我希望他們決定來這，因為我想要聽有關他們印度旅行的事。)
— 強調前面有關「結果」的那句:希望他們決定來這。
We’re no dessert in the house because you ate all the ice cream last night.
(在房子裡沒有甜點，因為你昨晚吃了太多冰淇淋了。)
— 強調後面「理由」那句: 你昨晚吃了太多冰淇淋了
可以進一步看看以下這個影片，理解 AS, SINCE , BECAUSE三者的比較:
7. for (conj.)
for 解釋作「因為」時是「連接詞」，要特別注意的是句子中的 for 前面要加上一個「逗點。
We must start early, for it will take two hours to drive to the airport.
我們得早點動身，因為開車去機場得花兩個小時。
搞清楚due to/ because of 的區別了嗎? 那麼你知道in which的用法嗎?