文法測驗

Choose the right sentence.

 (A) If you are attentive in class, you will not be able to follow the teacher.

 (B) Unless you are attentive in class, you will not be able to follow the teacher.

 (C) Be attentive in class, or you will be able to follow the teacher.

 (D) Be attentive in class, and you will not be able to follow the teacher.