This is a photograph ____our village.

Our village is in a valley.

It is between ____hills.

The village is on a ____.

Here is another photograph of the ____.

My wife and I ____ walking along the banks of the river.

We are on the left.

There is a boy in the water.

He is ____ across the river.

Here is ____ photograph.

This is the school building.

It is beside ____park.

The park is on the right.

Some ____ are coming out of the building.

Some of them are ____ into the park.

已知实数x、y满足 $\sqrt{3x+4}+y^2-6y+9=0$ ，则﹣xy的平方根等于____ ．

四大地理区域中，平均海拔高度最高的区域是（     ）

小明在做“凸透镜成像”实验时，将点燃的蜡烛放在凸透镜前20cm处，在透镜另一侧的光屏上观察到缩小的像。小明又把点燃的蜡烛与光屏的位置对调，则在光屏上能够呈现（   ）

a⁴b﹣6a³b+9a²b分解因式得正确结果为（　　）