A. too much energy
B. based on American designs
C. they are too costly
D. they are not reliable
E. quality control
F. free of charge
Robots are less popular in Britain today partly because ______.

A. for
B. from
C. to
D. of

A. The black hole is a region of space.
B. The black hole sucks in any object that passes by it.
C. The black hole is visible through an infrared telescope.
D. The black hole has no matter.