According to the passage, the formations on the surface of Mars could have been formed by
A. wind
B. volcanoes
C. earthquakes
D. water brought by comets
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浮点数的表示范围和精度取决于________。
A. 阶码的位数和尾数的机器数形式
B. 阶码的机器数形式和尾数的位数
C. 阶码的位数和尾数的位数
D. 阶码的机器数形式和尾数的机器数形式
Which of the following is TRUE about nuclear？
A. Nuclear is cost efficient.
B. Nuclear is the alternative energy to oil.
C. Industrialized countries are not likely to build any new plant.
D. Industrialized countries will make a nuclear energy-development plan.
某碱液25．00 mL以0．100 0 mol·L-1 HCl标准溶液滴定至酚酞褪色，用去20．00 mL，再用甲基橙为指示剂继续滴定至变色，又耗了6．50 mL，此碱液的组成为()。
A. NaOH
B. NaOH+Na2CO3
C. NaHCO3+Na2CO3
D. Na2CO3
The fact that there was water on Mars brings NASA the following with the exception of ______.
A. relief
B. fatigue
C. excitement
D. pleasure
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