秸秆主要含碳、氢、氧元素，近年来各地严禁在田间焚烧秸秆，焚烧秸秆造成的主要环境污染是（  ）

打点计时器是物理实验中用来记录物体运动情况的仪器。小明为了观察一个小木球下落的运动情况，他将小球上端连接一条纸带，纸带穿过打点计时器(如图所示)，让小球自由下落，打出的纸带由A到E，如图所示，关于小球运动状态和受力情况，下列说法正确的是（  ）

1879年10月，经过对1600多种材料进行几千次试验后，爱迪生制成了第一个可供实用的碳丝灯泡（灯丝由竹丝炭化后制成）。

碳丝通电后产生高温，在空气中立即烧断，这是因为____ （用化学反应方程式表示），所以碳丝灯泡必须抽成真空。

已知曲线y=x⁴+ax²+1在点（﹣1，a+2）处切线的斜率为8，a=（　　）

综合填空(用所给单词的适当形式填空。每词限用一次)

   Amy is thirteen. She comes from ____ . She’s in China with her ____ now. She’s a student in No.2 High School. She likes her school and all of her ____ . She thinks they’re very ____ to her. She likes Chinese, too. But she can’t ____  Chinese very well. Amy____ up very early every morning. She____  some milk and bread for breakfast. And she goes to school ____ bike.  She is never late.
   In the evening, she does____  homework and reads newspapers. She goes to bed at nine. She’s very____ every day.