题目

Tom ______to paint the fence but he got his friends to do it for him. A. supposed                     B. was supposing      C. had supposed            D. was supposed   答案：D  考查动词的用法。此处be supposed to意为：应该。句意：汤姆应该漆篱笆可是他让他的朋友为他做。   下列各组物质的分类正确的是（　　） ①混合物：水玻璃、水银、水煤气  ②电解质：明矾、冰醋酸、石膏 ③酸性氧化物：CO2、CO、SO3 ④同位素：1H、2H2、3H ⑤同素异形体：C80、金刚石、石墨  ⑥干冰、液氯都是非电解质． 　 A． ①②③④⑤⑥ B． ②④⑤⑥ C． ②⑤⑥ D． ②⑤