Black holes are actually filled with a lot of material. They are very （）.

A.Black holes are dead stars.

B.Black holes have gravity.

C.Black holes are invisible.

D.There is nothing as mysterious as a black hole.

Paragraph 2 __________ 查看材料

A.Is there proof that black holes really exist？

B.What are different types of black holes？

C.How are black holes formed？

D.How were black holes named？

E.What happens to the objects around a black hole？

F.What are black holes made of ？

Paragraph 3 __________ 查看材料

A.Is there proof that black holes really exist？

B.What are different types of black holes？

C.How are black holes formed？

D.How were black holes named？

E.What happens to the objects around a black hole？

F.What are black holes made of ？

A.A New Scientific Discovery: Black Holes

B.How Do Black Holes Come Into Being?

C.What Are Black Holes?

D.Travel Through A Black Hole

A．A New Scientific Discovery: Black Holes

B．How Do Black Holes Come Into Being？

C．What Are Black Holes？

D．Travel Through A Black Hole

Black holes exist but are difficult to observe.

A．Right

B．Wrong

C．Not mentioned

The most______(convince)evidence of black holes comes from research into binary star systems.

Black holes are part of space.

A．Right

B．Wrong

C．Not mentioned