同学们回想看看我们共学了哪些句型。本单元我们学习的是如何描述物体的位置。陈述句的格式为：sb. /sth.＋be(not)＋介词短语(方位)。如My book is(not)in my bag.我的书在/不在我的书包里。如果将这个句子改为一般疑问句就是将be动词提到句首，即为Is your book in your bag?寻问物体在哪儿要用到特殊疑问，结构为特殊疑问词where＋一般疑问句。如Where is your book?在这里提醒同学们注意的是主谓一致。还是这三个例子，如果要说明的不只一本书，而是几本书，它们分别为“My books are in the bag. Are your books in your bag? Where are my books?”

试一试：你能将方框内恰当的动词形式填入对话空白处吗？如果填对了，说明你掌握了主谓一致的基本原则，如果有错，不必着急，可以向你的老师或者同学请教。

am　　is　　are　　has　　have

I　1　John. I　2　a pen. It　3　on my desk. Tom is my friend. He　4　two pencils. They　5　in his pencil case. We are in the same(相同)school.

　　A mobile phone（手机）is in fact a small radio. A radio sends a person's voice over a long way to another radio. A voice that is sent by radio is called a signal（信号）. A radio signal travels very quickly.

　　Only a few years ago, mobile phones were very large. They needed large batteries（电池）. They had to be powerful（功率高）to send their signal to faraway places. This was because most cities had only one antenna tower（中继站）for mobile phones.

(1）The writer talks about ________ uses of a mobile phone.

(2）What does the writer think of today's mobile phones?

A．They are small but very powerful.

B．They are very popular and cheap.

C．They are very easy for us to use.

D．They are big enough to send a signal.

(3）What does the writer write the article（文章）for?

A．To give us some common knowledge of the mobile phone..

B．To introduce how the mobile phone works and what use it has.

C．To tell us what short forms of words mean in written messages.

D．To show us in what way the mobile phone is expected to develop.