Cathy said she speak four languages.[ ]
A. may
B. could
C. would
D. can
答案:B
我们身边的河流、湖泊受到污染主要原因是()
A.工业污水直排
B.生活污水和雨水混合直排
C.水体旁垃圾堆积
D.以上都是
岩石硬度