I'm Chinese ，but I am in England now. I can speak English. But I sometimes make mistakes with English. It was sunny yesterday. My class went to the park. I said，“Let's fly cats in the park. ”My classmates all laughed. I didn't know why. Then my teacher said，“Cats are animals. We can't fly them. But we can fly kites. ”“I know my mistake. I wanted to say kites，not cats. ”I said. Then we laughed again. That was funny.

下列大气环流图中，有关甲乙两地的说法正确的是（ ）

 图中A～E是操作化学常见的物质，已知A和E都可以作燃料，其中A是天然气的主要成分，请分析回答：

（1）反应①的化学方程式为　____ ；

（2）反应②中的产物B通常用____；

（3）E物质作燃料的优点是____（答一条即可）．

有若干标有“6V  0.5A”的小灯泡；此小灯泡正常发光时的电阻为　 ____Ω，电功率为　 ____W，若把两个这样的灯泡分别串联、并联后分别接在6V的电源上，则两种情况下电路的总功率之比为 ____