答案：
--Rita spent three hours _playing_ computer games last night.
--Why didn't you stop her _from doing_ that?It's bad for her eyes.
原题选项：
A.to play;to do
B.playing;from doing
C.to play;doing
D.playing;to do
求分析为啥选B
PS:因为是作业.so希望能简单易懂囧
几行长篇大论就免了OTZ..
