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【单选题】Black Holes Most scientists agree that black holes exist but are nearly impossible to locate.A black hole in the universe is not a solid object,like a planet,but it is shaped like a sphere (球体).Astr...
A.
Right
B.
Wrong
C.
Not mentioned
【单选题】有关视界圆说法正确的是( )
A.
视界圆只有一个
B.
在视界圆以外的物体即会复视
C.
不同的注视距离对应不同的视界圆
D.
视界圆是通过注视点与 2 眼角膜中央所画的圆。