It was after the invention of printing_______to publish large numbers of books and pictures.

A.were people able

B.that people were able

C.when were people able

D.people were able

It was after the invention of printing ________ to publish large numbers of books and pictures．

1. A.
   were people able
2. B.
   that people were able
3. C.
   when were people able
4. D.
   people were able