Tìm và sửa lỗi sai trong các câu sau:

1/ I (A) will leave the party early (B) because I (C) must (D) studying for my exam.

2/ I (A) stayed up (B) late last night because I (C) mustn't go to school (D) on Sunday.

3/ We (A) ought to not play football (B) as (C) it's raining (D) outside.

4/ You (A) mustn't (B) to drive a car (C) if you (D) don't have a driving licence.

5/ If you (A) want some useful (B) advice, you (C) have better talk to your parents (D) about your problem.

6/ I (A) had (B) stay at home 3 days (C) due to (D) snowing heavily.

7/ Because of his (A) poverty, he (B) has to (C) struggling (D) to make ends meet.

8/ (A) According to the rules (B) of this game, you (C) had better (C) not drop the ball.

9/ If you want (A) to get a higher mark in the next test, you (B) have better put (C) more effort (D) into vocabulary.

10/ We (A) shouldn't make an appointment (B) with this doctor. You (C) can see him whenever you (D) want.

11/ Look at the sky, it (A) is going to rain. (B) Thus, you (C) must bring (D) along a raincoat.

12/ I (A) ought to go home now (B) because i don't want (C) to walk in the (D) dark.