单项选择题

According to the passage, which of the following is TRUE

A．Energy only emits from Sagittarius A.
B．There are many strong energy sources.
C．Energy comes from a black hole.
D．Energy emits from any regions surrounding Sagittarius A.

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单项选择题

Were it not for the new telescope high in the Andes Mountains, researchers would not have argued that （）.

A．Sagittarius A is a powerful emitter of radio waves
B．a super-massive black hole contains as much as a million suns
C．Sagittarius A is a super-massive black hole
D．Sagittarius A lies just at the center of the Milky Way Galaxy

单项选择题

According to the German researchers, the energy source at the center of the Milky Way Galaxy ______.

A．has been covered up by vast clouds of dust and gas
B．still remains unknown to astronomers
C．has proved to be a black hole
D．actually provides power for the rotation of file great spiral of stars