若干个数排成一排就是等差数列．

选择合适的单词补全短文。

teacher;   man;  girl;  father;  woman

    Look! This is my family. The old ____ is my grandpa. And this is my ____. He is a teacher. The ____ in red is my mother. She is a ____, too. Who's that ____? Guess! Haha, it's me.

如图所示，固定的倾斜光滑直杆上套有一个质量为m的圆环，圆环与竖直放置的轻质弹簧一端相连，弹簧的另一端固定在地面上的A点，弹簧处于原长．让圆环沿杆滑下，滑到杆的底端时速度刚好为零．则在圆环下滑过程中

在横线上填上＞，＜，或=．

$-\frac{1}{4}$ ____ $-\frac{1}{3}$

－8____－6

$\frac{9}{10}$ ____0.9

如图，已知正比例函数y=2x与反比例函数y= $\frac{k}{x}$ （k＞0）的图象交于A、B两点，且点A的横坐标为4，