麻刀、纸筋、草秸用在抹灰层中起______作用,提高抹灰层的______,增加抹灰层的______,使抹灰层不易______。
参考答案:拉结;抗拉强度;弹性和耐久性;裂缝脱落
Which of the following statements about exchange-traded derivatives is FALSE()
A. They are liquid and provide price information.
B. They are standardized contracts.
C. They carry significant default risk.
下列关于Cl2用途的说法正确的是[ ]
A.Cl2有毒,不能用来给自来水消毒
B.饮用Cl2消毒的自来水不会对人体有任何伤害
C.Cl2是一种重要的化工原料
D.用Cl2与金属钠反应制取NaCl