_____ one of the most important inventions of the time, the computer helps people living in different countries to do a lot of things.

 　 A. Knowing to be 　　　 B. It was known　　　 　　

C. Known as　　　　　　 D. Which was known to be

________ one of the most important inventions of the time, the computer helps people living in different countries to do a lot of things.

1. A.
   Knowing to be
2. B.
   It was known
3. C.
   Known as
4. D.
   As was known to be

 _____ one of the most important inventions of the time, the computer

helps people living in different countries to do a lot of things

A. Knowing to be B. It was known C. Known as D. Which was

known to be

________ one of the most important inventions of the time, the computer helps people living in different countries to do a lot of things.

[　　]

________ one of the most important inventions of the time, the computer helps people living in different countries to do a lot of things.

[　　]