题目

A black hole is a place in space where gravity pulls so much that even light cannot get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying. Because no light can get out, people can’t see black holes. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently from other ones. Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the ma288里面有(　　)个72．