23．(2011黑龙江哈九中高三上学期期末考试) there’s no light on in the dormitory．they must have gone to attend the concert to be held on the campus，______ a. didn’t they? b. mustn’t they? c. haven’t they？ d. shouldn’t they? 24. (2011贵州省五校第四次联考) when asked the reason for moving to the usa，he said, “soccer is huge around the world apart from america， so that’s _________ i want to make a difference.” a. where b. why c. what d. how 25. （2011江苏启东中学考前训练）our english teacher often says we ______ remember enough english words. a. mustn’t b. shouldn’t c. cannot d. needn’t 26. (2011浙江四校联合体高三下学期开学考试)—mama, why can’t i work the math problem out?
