对复杂的有机物结构可用“键线式”表示。如苯丙烯酸1—丙烯酯： 可简化为 杀虫剂“阿乐丹”的结构表示为，若它在稀酸作用下能发生水解反应生成
— The housework is too much for me, Jack. —Sorry, but I can’t help______ it, Joan. I’ve got something important to do, you know. A. do B. doing C. to be doing D
继“表叔”、“房叔”、“雷人”等一批违纪腐败官员因网络举报落马后，近期又有人通过微博实名举报地方高层官员，引发了社会更为强烈的关注。
the climate changes so much has caused many discussions among the scientists A What B Which C When D That
.已知向量a＝(1,0)，b＝(cosθ，sinθ)，θ∈，则|a＋b|的取值范围是( ) A． [0，] B． [0,2] C． [1,2] D． [，2]
There was room for all of us, and the sleeping bags kept the night coldness away. We would listen to the sound of the river, and hear the coyotes (土狼) howling along the hills not far away. Those w
浩瀚的宇宙一直是人类探索的内容，尽管还有许多未知的领域，但人类一刻也没有停下探索的脚步。据此回答下面试题。 23、地球和人类是如何产生的
