江苏等省城镇每百户电冰箱等的拥有水平比较如果每套组合音响的价格是200元，那么陕西省

命题“若a•b=0，则实数a=0或b=0”的否命题是______．

根据句意及所给提示，补全单词或用单词、固定短语、固定搭配的正确形式填空。

1. I w_____ if you can finish the work on time.

2. People in Korea are supposed ______ (bow) when they meet for the first time.

3. In the old days, the workers were made ______ (work) eleven hours a day.

4. I can't find ______ (适当的) words to describe her beauty.

5. I have ______ (借) his book for two weeks. I have to return it now.

K线图中十字星的出现表明( )

A．多方力量略微比空方力量大一点
B．空方力量略微比多方力量大一点
C．多空双方的力量不分上下
D．行情将继续维持以前的趋势，不存在大势变盘的意义

加入适量除硫剂（）是正确的。

A.降低钻具的腐蚀

B.在钻开含硫地层前60m添加除硫剂

C.在钻开含硫地层后添加除硫剂

D.碱式碳酸锌的加量为2%

E.碱式碳酸锌的加量为20%

冷弯往往不能一次成形，常温下多次滚压会使材料机械性能恶化，所以当滚弯成形的弯曲半径（）时，应采取加热滚弯。（注：t代表板厚）

A.R<30t

B.R>20t

C.R<20t

D.R<15t