已付款占比为计算公式为：已付款合计/合同金额。

小明找到了几个相同的小灯泡，他将这些灯泡串联起来使用，发现串联的个数越多，用电流表测得的电流越小，他想探究“电路中的电流大小与用电器串联的个数是什么关系？”请帮助他完成部分探究过程．

（1）主要器材：

（2）实验步骤：

（3）设计记录实验数据的表格：

在实验室的下列做法中正确的是[ ]

A．为了节约药品，用剩的药品应放回原试剂瓶

B．为了获得感性认识，可触摸药品或尝药品的味道

C．为了能看到标签，倾倒试液时，标签不能向着手心

D．为了安全，给试管里的液体加热时，试管口不能朝着有人的方向

阅读理解。

     Tea drinking was common in China for nearly one thousand years before anyone in Europe had ever heard

about tea. People in Britain were much slower in finding out what tea was like, mainly because tea was very

expensive. It could not be bought in shops and even those people who could afford to have it sent from

Holland did so only because it was a fashionable curiosity. Some of them were not sure how to use it. They

thought it was a vegetable and tried cooking the leaves. Then they served them mixed with butter and salt.

They soon discovered their mistake but many people used to spread the used tea leaves on bread and give

them to their children as sandwiches. Tea remained scarce and very expensive in England until the ships of

the East In-dia Company began to bring it direct from China early in the seventeenth century. During the next

few years so much tea came into the country that the price fell and many people could af-ford to buy it. At the

same time people on the Continent were becoming more and more fond of tea. Until then tea had been drunk

without milk in it, but one day a famous French lady named Madame de Sevigne decided to see what tea tasted

like when milk was added. She found it so pleasant that she would never again drink it without milk. Because

she was such a great lady her friends thought they must copy everything she did, so they also drank their tea

with milk in it. Slowly this habit spread until it reached England and today only very few Brit-ons (British

people) drink tea without milk. At first, tea was usually drunk after dinner in the evening. No one ever thought

of drinking tea in the afternoon until a duchess (公爵夫人) found that a cup of tea and a piece of cake at three

or four o'clock stopped her getting" a sinking feeling" as she called it. She invited her friends to have this new

meal with her and so, tea-time was born.

1. Which of the following is true of the introduction of tea into Britain?

A. The Britons got expensive tea from India.

B. Tea reached Britain from Holland.

C. The Britons were the first people in Europe who drank tea.

D. It was not until the 17th century that the Britons had tea.

2. This passage mainly discusses _______.

A. the history of tea drinking in Britain

B. how tea became a popular drink in Britain

C. how the Britons got the habit of drinking tea

D. how tea-time was born

3. Tea became a popular drink in Britain ______.

A. in eighteenth century

B. in sixteenth century

C. in seventeenth century

D. in the late seventeenth century

4. We may infer from the passage that the habit of drinking tea in Britain was mostly due to the

     influence of _________.

A. a famous French lady

B. the ancient Chinese

C. the upper social class

D. people in Holland

电力晶体管（GTR）有哪些特点？

离心泵为什么要密封？