Explaining Reasons with “Because” | #english

Correct Answer: 2. She is smiling because she passed the exam.

Here’s why:

• Sentence 1 is incorrect because it omits the subject after “because” (“I stayed up late” is needed).

• Sentence 3 is incorrect because “because of” should be followed by a noun or noun phrase, not a full clause (“because they missed the bus” is correct).

source