跨经度最广的大洲和大洋分别是( ) A．亚洲和太平洋 B．大洋洲和太平洋 C．南极洲和北冰洋 D．南极洲和太平洋
下列各组气体全部可以用浓H2SO4来干燥的一组是（）。A.CH4、H2、CO、NH3 B.CO2、H2、SO2、Cl2C.CO、CH4、HCl、HBr D.SO2、CO2、H2、H2S
宇宙中含量最多的元素是氢元素，科学家发现，这些氢元素除了以H2存在外，还有少量以H3存在。下列有关H3的说法正确的是 （ ） A.它是一
My father ________ to Nanjing twice. A. has been B. has gone C. have been D. have gone
--- An ant has two stomachs --- one for itself, one for others. --- Really? Quite interesting. I ____ anything about it. A. don’t know B. have known C. haven’t known
Watching TV is a very popular pastime in the UK but what kind of programmes do British people like to watch? Well, the most-watched TV programmes every week are very popular dramas that are usually on
（2013•临沂）当你走在放学回家的路上，突然间狂风大作，电闪雷鸣，这时你会急忙找避雨地点，并迅速跑过去．如图是该过程的反射活动图解，请你
、中部高，四周低 