聚丙烯酰胺浓度达到（）g/L可显现干扰浮选正常分选。
A.1.5
B.2.5
C.3.5
D.5
参考答案：C
The 8.8 quake in central Chile caused widespread damage,destroying lost of buildings and hundreds of thousands Of people__________ .
A．to affect
B．affecting
C．affect
D．affected
最常见的引起白瞳症的眼病是（）
A.Coats病
B.永存原始玻璃体增生症
C.白内障
D.早产儿视网膜病变
E.转移性眼内炎
