And in that way it has been proved that the ...

[ Grammar ]

And in that way it has been proved that the radioactive elements are constantly ______ and that they produce at the end ordinary elements, principally helium and lead.

A. disintegrating

B. to disintegrate

C. being disintegrating

D. disintegrated

Select your answer:
A B C D E

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Choose the sentence with the correct placement of commas.

A. How do I turn on this computer, Mr. Thomas?

B. How do I, turn on this computer Mr. Thomas?

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