1. 答案:A.把该句还原成主动句即:Somebody saw the boy ____ on the sports ground.此题含有“感官动词saw + 宾语the boy + 宾语补足语play”结构。考查宾语the boy和宾补动词play之间的关系为主动关系,答案只能是play或playing.但是如果该句变成被动语态后,如果主动句答案为play,则被动句时须改成to play(即补上主动句中被省略的不定式符合to);如果主动句答案为playing,则被动句时无需改变,还是playing.所以答案只能是:to play 或 playing,最终选择A。2. 此题答案可以是以下两种:1)lasted 炎热的天
1、see sb. do see感官动词,后面接了不定式,省略to但用做被动语态的时候,要还原to即:The boy was seen to play on the sports ground(=sb. saw the boy play on the sports ground)选AThe hot weather last