根据实验室制取气体的常用装置图，回答问题： (1)图中 ① 仪器名称是 ______ 。 (2)用 A 装置制取氧气的化学方程式： ______ 。 (3)实验室既可制取二氧
KCl和KNO3的溶解度表及溶解度曲线如图所示，下列说法不正确的是 （ ） 温度/℃20304050 溶解度S/gKCl 34.0 37.0 40.0 42.6 KNO3 31.6 45.8 63.9 85.5 A．甲表示
生长在沙漠中的仙人掌，其肉质茎的细胞中含量最多的化合物是( ) A．蛋白质 B．脂质 C．糖类 D．水
The problem ______ many children, especially girls, have ________ school is getting more and more serious. A. which; got out of B. that, dropped out of C. that, fallen out of D. which, run out of
设F为抛物线y＝－x2的焦点，与抛物线相切于点P（－4，－4）的直线l与x轴的交点为Q，则∠PQF的值是 ．
下列有关有机物的说法正确的是 A．蛋白质、淀粉、纤维素、蔗糖都属于有机高分子化合物 B．乙醇、乙酸、乙酸乙酯可以用饱和碳
—Do you still remember the first time we met, Linda? —Sure. You a meeting in our classroom. A．were addressing B．had addressed
Testing has replaced teaching in most public schools. Pretests, drills, tests, and retests fill my own children’s school week. They know that the best way to read a textbook is to look at the questi
