Dear Andy

I’m in London now. It’s the c  86  of England. I enjoy everything here except the food. I dislike English food. I miss dumplings and noodles.  Of course I never  s  87   missing you.

Things here are quite d  88  from those in China. T  89 in England goes on the left of the road. And if you want to go the other side of a road, you can have many ways: a subway(地铁), a footbridge or a zebra c  90  . And in some places, you can see black and white poles(杆). There is a button（键）on each of them. You can press the button to tell the drivers you want to cross the road. They usually stop their cars to let you go.

Taxis in London are really e  91  , so if you come to London, you should have enough m  92   with you. Taxi drivers are usually friendly. They are always ready to help you. And they must take exams b  93  they become taxi drivers.

London a   94   has the biggest underground system(系统) in the world. It’s easy to go the w  95   way if you are not careful.

Yours

Li Bing

在导爆管起爆网路中用雷管起爆导爆管时，常采用反向起爆方法，反向起爆法是指将导爆管端头指向雷管（）

A.头部

B.中部

C.底部

D.端部