问题 选择题
下列说法正确的是(  )

A.把密度大于水的物质制成的物体放在水中,一定下沉至水底

B.把密度等于水的物质制成的物体放在水中,不可能漂浮在水面上

C.密度小于水的物体也有可能悬浮在水里

D.将质量相等的实心铁块和木块放在水中,铁块受到的浮力一定小于木块受到的浮力

答案

答案:D

阅读理解

阅读理解。

        Going to a friend's house is very exciting. You may spend time with a friend and get to see where he lives.

So remember to be polite.

        When to arrive

        The first thing to remember is that when a friend invites you over, you need to arrive on time. If your

friend tells you to come "around 3:00", that means you can turn up a little bit after 3:00. But usually it is a good

idea to arrive at the right time. 

        What to bring

        Often it is also nice to bring something to your friend's house. This could be a box of chocolates for you

two to share, or maybe a movie that you can watch together. You can also bring some flowers. A little gift is a

nice way to show your friend that you are excited to be at his house.

        How to greet (问候)

        When you visit your friend's house, you may also meet his parents. You should tell them who you are and

they may tell you their names. As a child, I went to visit my friend Paul. I called his parents by their first names

John and Mary. But now I know it is more polite to call them Mr. or Mrs. Smith. This will show them more

respect (尊重) and then they may tell you to call them by their first names. Another way to show respect is to

call them Madam or Sir.

        It is a cool thing to visit a friend's house. Be polite to your friend and your friend's parents, and you will

be invited again!

1. If you are told to get to your friend's house around 5:00 p.m., it is polite to arrive at_____[ ]

A. 5:02 p.m.

B. 4:50 p.m.

C. 4:30 p.m.

D. 5:30 p.m.

2. When the writer was a child, he called his friend's father _____.[ ]

A. Smith

B. John

C. Mary

D. Paul

3. The passage mainly (主要) tells us _____.[ ]

A. when to arrive at your friend's house

B. how to greet people

C. what to bring to your friend

D. how to be a good visitor

单项选择题