静电电压最高可达 ( ) ,可现场放电,产生静电火花,引起火灾。
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下列哪个酶是三羧酸循环中的限速酶()
A. 己糖激酶
B. 6-磷酸果糖激酶-1
C. 丙酮酸激酶
D. 葡萄糖6磷酸酶
E. 异柠檬酸脱氢酶
How long do the children have swim lessons every week?
A. For about an hour.
B. For about seven hours.
C. For about four hours.
D. For about eight hours.
What do we know about the writer’s swimming skills?
A. The writer is a great swimmer.
B. The writer can only swim slowly.
C. The writer doesn't know anything about swimming.
D. The writer can't swim very well.
What does Cameron think of swimming?
A. He doesn't like swimming at all.
B. He is overly confident about swimming.
C. He expects to swim in summer the most.
D. He thinks it's the best way to exercise.
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