锥塞式锚具按材料分有（）
A、钢质锥塞式
B、预应力锥塞式
C、热铸锥塞式
D、冷铸锥塞式
参考答案：A, C, D
After school we went to the reading-room to do some reading, only to be told that it .
A．is decorated
B．was decorated
C．was being decorated
D．is being decorated
HPAM溶液的粘度随（）的变化通常为盐敏性。
A、矿化度
B、分子量
C、水解度
D、温度
