题目

The sweater ________ Tina's. She's the only one who wears such colorful clothes.A.can't be B.might be C.must be D.could be 答案：【答案】C【解析】句意：这件毛衣一定是蒂娜的。她是唯一一个穿这么五颜六色衣服的人。考查情态动词表推测。can't be不可能是；might be可能是；must be一定是；could be可能是。由“She's the only one who wears such colorful clothes.”可知，蒂娜是唯一一个穿得这么五颜六色的人，故毛衣一定是蒂娜的。故选C。某反应为2X+3O22CO2+4H2O，根据质量守恒定律则X的化学式是（ ）A．H2B．CH4C．CH4OD．C2H6O