A ______ dog is barking ________ at us. We hate it.

Why don’t those children go to school They’re tooyoung to work in the factory. –Maybe their parents can’t_______theireducation.

Susan’s parents have bought -a large house with a swimming pool in Paris.–It be very expensive.

21．This book is said to be a special one, which____many events not found on other history books.

The law of over－learning explains why cramming (突击学习) for an examination, though it may result in a passing grade, is not a ________ way to learn a school course.[ ]