Communication satellites generally use solar cells as their source of electric power, although some test satellites have used thermoelectric generators.

Our lives are intimately bound up with theirs.() A. ten...

单项选择题Our lives are intimately bound up with theirs.()

It is absurd to predict that the sun will not rise tomo...

单项选择题It is absurd to predict that the sun will not rise tomorrow.()

The ship's generator broke down, and the pumps had to b...

单项选择题The ship's generator broke down, and the pumps had to be operated by hand.()