完成下列作图．

（1）图1中的OA是光从空气斜射到水面，经水面反射的一条光线，请作出它对应的入射光线和入射光线的折射光线．

（2）将图2中的灯和控制灯的开关连入电路．

    There have been many comparisons (比较) made between London Underground and New York Subway. They are the best known public transport systems (公共交通运输系统) in the world and each is a key part of one of the greatest cities of the world. The two systems have many things in common(相同), including their ages and fame（名声）, but there are also important differences.

    The following table shows some of the similarities (类似）and differences.

一辆汽车3小时行310千米， 平均每小时行多少千米？ （用分数表示） 

关于东南亚的叙述，正确的是（   ）

按一定规律排列的一列数，依次为1，4，7，…，则第n个数是____