问题 填空题

如图所示,是四根高压输电线上的一个装置,利用它将四根导线并联起来,相当于增大了导线的横截面积,从而减小了导线的     ,以达到                              的目的。

答案

电阻     减少输电线上电能的损失 (能写出电能损失即可)

①四根导线并联在一起,等效成一根导线,相对于其中的任何一根导线,其横截面积变大了;导体的电阻大小与导体的横截面积有关,在其他因素不变的情况下,导体的横截面积越大导体的电阻越小;所以横截面积增大,导体的电阻减小.

②在输电电压U输一定的情况下,由公式P=U2 /R 可知,输电导线电阻R越小,输电功率损失越小,因此可减少输电电能损失.

阅读理解

    In England, we look forward to our birthdays for 364 days a year!

We invite special people to celebrate it with us.

The Presents

Presents are opened as soon as the children are awake. They can’t wait for the birthday cake later in the day!

The Cards

Friends and family send birthday cards. Sending birthday cards is a custom (风俗) that began in England about 100 years ago.

The Party

The birthday child will have a party to which friends and family are invited. Visitors to the party bring presents for the birthday child. The children play games such as musical chairs and pass the parcel (包裹).

The Cake

The birthday cake is decorated on a theme (主题). A candle for each year is lit and placed on top and the child blows out the candles making a wish. We don’t put objects inside the cake as stated on many websites.

The Bumps (碰撞)

It used to be traditional for the birthday child to have the bumps. Friends would hold the child by the legs and under the arms and lift the child up and down bumping them gently on the ground. The number of bumps given is the age of the child plus one for extra good luck. As this can be dangerous, clapping (拍手) is often done instead.

The Sweets

Some children do take sweets to school to share with their classmates on their birthdays.

小题1: In England, the birthday present is opened _____.

A.before the child wakes up

B.immediately after the child wakes up

C.as soon as the child gets up

D.during the birthday party小题2: If Alice is celebrating her 7th birthday, how many bumps will she be given?

A.Six.

B.Seven.

C.Eight.

D.Nine.小题3: Which of the following facts about birthdays in England is NOT true?

A.All the children will receive birthday cards on their birthdays.

B.Clapping is often done for the birthday child.

C.Objects meaning good luck are usually placed inside the birthday cake.

D.Nowadays children may share sweets with their classmates on their birthdays.小题4: What would be the best title for this passage?

A.How birthdays are celebrated in the world

B.Where to hold an English birthday party

C.What to send when invited to a child’s birthday

D.How English children celebrate their birthdays

选择题