a仪器的名称是____；实验室利用甲装置制取氧气时，a仪器中所盛试剂为____（填名称）．实验结束时，为防止水倒吸，正确的操作是：先____，再____．用装置乙制取二氧化碳，反应的化学方程式为____，实验时，如果二氧化碳始终收集不满，可能的原因是____（写一种）．

如图为“2008年年底我国北方地区、南方地区、西北地区、青藏地区的面积、人口、GDP值百分比统计资料图”（注：不含港、澳、台地区）．我国四个地区中面积最大，人口最多，GDP总值最高的分别是（　　）

用所给动词的适当形式填空，完成短文

 Children’s Safety

I ____(talk) to some students. I ____(ask) about safety rules when they ____(be) younger. Their rules were very good.

John ____(say), “I couldn’t play in the kitchen.” His mum and dad didn’t ____(like) that.

Jennifer ____(can) play the piano and she could also ____(play) games in the living room. When her mum and dad ____(not, be) home, she couldn’t cook.

Tom could play in the bedroom or the living room. He couldn’t ____(play) in the bathroom or the kitchen.

What ____(be) your safety rules when you were young? ____(talk) to younger students about these and ____(help) them.

如图示意水泥工业的布局要求与我国长江中下游平原某城市的区域条件。读图完成下题。