A:He cleaned his room yesterday.
B:He cleaned his room the day before yesterday.
C:He cleaned his room last weekend.
某超市从厂家以每件21元的价格购进一批商品,该超市可以自行定价,但物价局限定每件商品加价不能超过售价的20%,则这批商品的售价不能超过____元.
人呼吸时,呼出的气体成分是( )
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除夜作 高适 旅馆寒灯独不眠, 客心何事转凄然? 故乡今夜思千里, 霜鬓明朝又一年。