A:水对石头的压强比对木头的小
B:木头受到的浮力大于它自身的重力
C:鱼受到的浮力等于它排开水的重力
D:石头受到的浮力等于它自身的重力
A. She's my mother.
B. I have a happy family.
C. What's this?
D. This is my father.
Rose: ____
Tom: It's a picture (照片) of my family.
Rose: Who's this?
Tom: ____
Rose: Who's she?
Tom: ____ And this is me.
Rose: Are you happy?
Tom: Yes. ____
下图是探究铁锈蚀条件的装置。调节L端与R端的液面高度一致,塞紧木塞,一周后观察。下列推断错误的是( )
下列命题:
①三点确定一个圆;
②从圆外一点引圆的两条切线,它们的切线长相等;
③所有的正方形都有外接圆;
④三角形的外心到三角形各个顶点的距离相等;
正确的有( )
下列化学用语正确的是