根据下列材料回答问题。 材料一：2006年～2009年重庆市农村与城镇居民人均纯收入比较图 注：2009年我国农村与城镇居民人均纯收入分别为520
与图1所示水系形态相对应的地表形态特征是 甲 乙 丙 丁 A．甲——平行岭谷
长为2个单位长度的木条放在数轴上，最少能覆盖＿＿个表示整数的点，最多能覆盖＿＿＿个表示整数的点。
如图,正方形OABC的边长为1,点D、E分别为、BC的中点,试求cos∠DOE.
用化学用语填空： (1)镁 ；(2) 2个氮气分子 ；(3)5个硫酸根离子 ； (4)甲烷 ；(5)+6价的硫元素
If you look for a book as a present for a child, you will be spoiled for choice even in a year there is no new Harry Potter. J.K Rowling’s wizard is not alone. The past decade has been a harvest f
Tom doesn’t like maths, ______ he likes Chinese a lot. A. and B. but C. or D. so
The weather turned out to be fine yesterday. I _______ the trouble to carry my umbrella with me. A. should have taken B. could have taken C. needn't have taken
