家庭厨房中经常发生一些变化，其中属于物理变化的是[ ] A．未吃完的饭菜变馊 B

选用动词的正确形式填空。

     Lisa Hunter __1__(be) 18 years old. She __2__(finish) high school last week. She __3__(go) to an

all-girl-school because her mother said she would study better if there were not any boys around. Lisa

knows what she wants __4__( do )with her own life. She __5__(be) an engineer when she __6__(grow)

up . Because she likes __7__ (work) out difficult math problems. She __8__( take) a year off before she

goes to university. She __9__(go )to Italy because she __10__(like) the people, the warm weather and

the food there.

如图所示，带电荷量为Q的正点电荷固定在倾角为30°的光滑绝缘斜面底部的C点，斜面上有A、B两点，且A、B和C在同一直线上，A和C相距为L，B为AC中点．现将一带电小球从A点由静止释放，当带电小球运动到B点时速度正好又为零，已知带电小球在A点处的加速度大小为

g

4

，静电力常量为k，求：

（1）小球运动到B点时的加速度大小．

（2）B和A两点间的电势差（用Q和L表示）．

The weather in Guangzhou is hotter than_____ in Harbin.

A．that

B．it

C．this

D．what

（）不是摩尔根提出的人类社会的阶段

A、蒙昧期

B、野蛮期

C、过渡期

D、文明期

囟门高突称为（）

A.解颅

B.囟平

C.囟填

D.囟陷

E.头发稀疏