题目内容：
According to the teacher, why do the students of English class rarely volunteer to answer questions even when they know the answers?
A.Because the students can not understand the questions clearly.
B.Because the students are not very confident in their oral English and they lack practice in public speaking.
C.Because the students are afraid of making mistakes.
D.Because the students want to give teachers an impression that they are modest.
参考答案：