Thatyoungboywasknocked______byapassingcarAonBa

That young boy was knocked ______ by a passing car.

A. on

B. at

C. in

D. down

正确答案：D
19．答案为D这个小男孩被经过的汽车撞倒了knockdown“撞倒”；knockon“敲击”；knockat“敲(门)”；knockin“(把钉子)钉入”