眼底可能出现棉绒斑的疾病有（）
A.恶性高血压
B.慢性肾衰竭
C.糖尿病视网膜病变
D.眼缺血综合征
E.早产儿视网膜病变
参考答案：A, B, C, D
He bought a new car ______ engine was very powerful. [ ]
A. which
B. its
C. whose
______是水污染的主要根源，______、______、农药、______等都会污染水环境．
