I could hardly hear her at the back.
A:always
B:almost not
C:often
①自习课上,同学们安静地学习
②一个小女孩在个人独处的场合将果皮扔进垃圾箱
③一位男生躲在校园的角落里吸烟
④非得在老师的监督下才完成作业