人体的渴觉中枢、渗透压感受器、血糖调节中枢、体温调节中枢分别位于
A:大脑皮层、下丘脑、下丘脑、大脑皮层
B:下丘脑、下丘脑、下丘脑、下丘脑
C:脊髓、下丘脑、大脑皮层、下丘脑
D:大脑皮层、下丘脑、下丘脑、下丘脑
①二次三项式ax2+bx+c的最大值为4;
②4a+2b+c<0;
③一元二次方程ax2+bx+c=1的两根之和为﹣1;
④使y≤3成立的x的取值范围是x≥0.
其中正确的个数有( )
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. ____
有一个边长为50cm的正方形洞口,要用一个圆盖去盖住这个洞口,那么圆盖的直径至少应为( )
在含有Fe3+、Fe2+、Cu2+的溶液中加入铁粉,充分反应后,固体残渣用盐酸处理有气体放出,则与铁粉反应后的溶液中最多的离子是