29 BCD都是动词语序问题,只有a对。例c该是where I can put the book。30 a 缺介词 正常语序live in this room,改成which从句 which room to live in。b有个with就对了。有with,用这支笔写,如果没有with就变成写这支笔了。31 同上,介词问题。live in the room,改which room to live in的时候in不能少。不是活房子,而是在房子中过活。