China has lately been faced with serious issues of product safety. In Panama, it is said that medicine made with a poisonous chemical sickened some people. A Chinese company had identified it as di
推理是一种重要的学习方法。下列推理中正确的是 （ ） A. 氧化物中含有氧元素，则含氧元素的物质一定为氧化物。 B.
近代以来，中国民族工业在夹缝中生存，步履维艰，发展缓慢，其原因包括 ①列强的压制 ②中国民族资产阶级的先天不足 ③清政府的盘剥
—Hi, Lucy．Do you know where Linda is? —She________in the library．I saw her there just a few minutes ago． A．shall be
They want to make it clear to the public ________ they are doing an important and necessary job. A. what B. which C. that D. all
钢铁是使用最多的金属材料。 （1）铁制品在一定条件下能生锈，疏松的铁锈不能阻碍里层的铁继续与 ① 反应，因此铁制品可以进一步锈蚀。防
如图所示，竖直放置的轻弹簧一端固定在地面上，另一端与斜面体 P连接，P与斜放的固定挡板MN接触且处于静止状态，则斜面体P此刻所受到的外力个数
