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