电气控制系统中常用的保护环节有哪几种？

It has been sunny these days, so I ______ it ______ tomorrow.

A．think , won’t rain

B．don’t think, will rain

C．think ,doesn’t rain

D．don’t think , rains

下列计算正确的是[ ]

A．a³+a⁴=a⁷

B．a³a⁴=a⁷

C．（a³）⁴=a⁷

D．a⁶÷a³=a²

患者腰痛重着，畏寒喜温，伴双下肢冷凉，舌苔白腻，脉沉紧，应认为是 （）

A.寒湿腰痛

B.寒湿痹证

C.肾阳虚腰痛

D.风湿痹证

E.风湿腰痛

34. People in China are proud of _____ we have achieved in the past ten years.

A．that

B．which

C．what

D．How

黄豆酱的氨基态氮的含量应（）。

A.≥1.0%

B.≤1.0%

C.≥0.60%

D.≤0.80%