问题 问答题 简答题

海员是怎样精确测定经度的?

答案

参考答案:

要精确测定经度,就必须有高度准确地保持零度子午线时间的时钟,即格林威治时间的时钟,这个时钟就是人们通常所说的天文钟。海员首先借助六分仪和天文表确定当地时间,然后根据当地时间和格林威治时间的时差来确定当地的经度。

阅读理解

阅读理解。

     Like most English children, I learned foreign languages at school. When I made my first visit to the

United States, I was sure I could have a nice and easy holiday without any language problem. But how

wrong I was!

     At the American airport, I was looking for a public telephone to tell my friend Danny that I had arrived.

An American asked if he could help me. "Yes," I said, "I want to give my friend a ring."

     "Well, that's nice. Are you getting married?" he asked. "No," I replied, "I just want to tell him I have

arrived." "Oh," he said, "there is a phone downstairs on the first floor." "But we're on the first floor now,"

I said.

     "Well, I don't know what you are talking about Maybe you aren't feeling too well after your journey,"

he said."Just go and wash up, and you will feel a lot better." And he went off, leaving me wondering where

on earth I was: At home we wash up after a meal to get the cups and plates clean. How can I wash up at an

airport?

     At last we did meet. Danny explained the misunderstanding: Americans say "to give someone a call", but

we English say "to give somebody a ring". When we say "to wash your hands", they say "to wash up". And

Englishmen start numbering from the ground floor so the first floor is the second for Americans.

1. The writer went to America by ______.

A. plane

B. ship

C. bus

D. train

2. The writer went to America for ______.

A. education

B. business

C. holiday

D. friendship

3. The American thought "a ring" should be a ______.

A. phone call

B. present

C. person

D. letter

4. Englishmen usually wash up ______.

A. after dinner

B. after a journey

C. when they are tired

D. before they telephone someone

5. The third floor in England is the ______ floor in America.

A. first

B. second

C. third

D. Fourth

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