A:农田生态系统
B:森林生态系统
C:沙漠生态系统
D:河流生态系统
During holidays,Kitty usually goes to see the exhibits in many museums,such as the history museum,the art museum,the museum of science and technology and the museum of natural history.There are thousands of wonderful things in museum.There are paintings,sculptures(雕塑),costumes(服饰),swords(剑),ancient animal bones and plants,stuffed animals(动物标本)and many others.It is always a good review of history to visit those museums.It is also a great way to learn more things by myself.
麻雀曾被认定为主要害鸟,20世纪50~60年代,我国曾开展过大规模的“剿灭麻雀”运动,现在又发出了保护麻雀的呼声,对此以下说法不正确的是( )
a.氧化性 b.还原性 c.不稳定性 d.挥发性 (用序号填空)
①浓硝酸要避光保存在阴凉处,是因为浓硝酸具有 ____ ;
②浓硝酸可使铁、铝产生钝化现象,是因为浓硝酸具有 ____ ;
③打开浓硝酸的瓶盖,可见到白雾,是因为浓硝酸具有 ____