某工厂排放的酸性废水中含有较多量的Cu2+，对作物和人畜都有害，欲采用化学方法去掉有害成分，最好加入下列物质中的( ) A.食盐和硫酸
下面关于两个互成角度的匀变速直线运动的合运动的说法中正确的是（ ） A．合运动一定是匀变速直线运动 B．合运动一定是曲线运动 C．合运动可能
I’m very happy to hear from you, but know that you are visiting China next month. I will be freely at that time and I’m eager to meet you. Please tell me your flight numbers and arrival time so
如图所示，光滑杆偏离竖直方向的夹角为θ，杆以O为支点绕竖直轴旋B转，质量为m的小球套在杆上可沿杆滑动，当其角速度为ω1时，小球旋转平面在A处
某中学地理兴趣班计划分甲、乙、丙、丁四个小组沿右图中四条线路进行攀登活动，你认为哪个小组的攀登线路坡度最缓A．甲B．乙 C．丙D．丁
In the U.S., people prefer waiting for a table to sitting with people they don’t know. This means a hostess may not seat a small group until a small table is available, even if a large one is. If yo
2008年1月 12 日，我国南极内陆冰盖考察队17名队员成功登上南极内陆冰盖最高点—一海拔 4093米 的冰穹A，开展实际性科学考察行动。这是我国第二次通
When I left, mother ___ me that I should take care of myself while I was in the countryside. A. remembered B. reminded C. was reminded D. asked
