2011年4月14日，“金砖国家”巴西、俄罗斯、印度、中国和南非领导人第三次正式会晤在三亚举行。“金砖国家”的崛起，提升了新兴经济体在国际政治
设阿伏加德罗常数为NA，则正确说法正确的是（ ）A.常温常压下，11.2 L甲烷中含有的氢原子数为2NAB.标准状况下，0.3 mol二氧化硫中含有氧原子数0.3NAC
The article is too long and should be _______ by half. A. cut down B. cut off C. turned down D. turned off
一艘轮船从东海驶入长江后，它所受到的浮力 ( ) A.变小 B.不变 C.变大 D.不能确定
下列相关反应的离子方程式书写正确的是（ ） A．4molFe 在5molCl2中点燃反应：5Cl2+4Fe=2FeCl2+2FeCl3 B．氯化铁溶液中通入硫化氢：2Fe3++H2S=2Fe2++S↓+2H+ C．NH4Al
Had Jack received six more votes in the election last week, he______ the chairman of the students’ union now. A. must have been B. would have been C. were D. w
John asked me _______ to visit his uncle’s farm with him. A．how would I like B．if or not would I like C．whe
