①双曲线的解析式为y= 40x (x>0);②E点的坐标是(5,8);③sin∠COA= 45 ;④AC+OB=12 5 .其中正确的结论有( )
A:1个
B:2个
C:3个
D:4个
—I think I've got a bad cold, Doctor, Shall I take some medicine?— No need. Your body itself is able to the virus. Just drink more water and rest.
化学“家庭小实验”是利用家庭日常生活用品进行化学学习和探究的活动,下列实验中用家庭日常生活用品能够进行的是()①检验纯碱中含有CO32-②除去热水瓶内壁上的水垢③检验鸡蛋壳能溶于醋酸④检验自来水中含有Cl-