题目

能用于鉴别空气、二氧化碳和氧气的最简便方法是    A.带火星的木条     B.加入澄清石灰水    C.燃着的木条    D.闻气味 答案：CThe lady said she would buy a gift for her daughter with the _____. [     ]A. 20 dollars remained B. 20 dollars to remain C. remained 20 dollars D. remaining 20 dollars