木质地板的特点有（）。
A.自重轻
B.有弹性
C.舒适度好
D.耐火性强
参考答案：A, B, C
—Could you let me know ______ yesterday?
—Because the traffic was heavy. [ ]
A. why did you come late
B. why you came late
C. why do you come late
D. why you come late
