我国古代边防建设的代表——长城始建于（）A、春秋战国 B、秦汉 C、唐 D、明

                             Table Manners in America   

          Don’t circle your plate with your arms. If you do so, you will

become the focus(焦点) of the table. Everyone would wonder,"Is

there anything wrong with the food?" This may give a wrong message

that you don't like the food or something like that. 

     Don't push the plate back when finished. Leave it where it was.

Do you want to let the hostess(女主人) know that you've just

done a labour?

     Don't lean(倚靠)  back and say"I'm through"or"I'm full". Just

put the fork and knife across the plate. That's all. 

     Don't cut up everything before you start to eat. Cut only one

or two bites(块) at a time. 

     Never take a huge mouthful of anything. Do you want to show

how hungry you are? Don't do that. It's not so good.    

     It's never good   to reach across the table for anything. If the

thing you want is not at hand, simply ask the nearest person for

help, like “Mrs Smith, could you pass me the dish?”

1. If you are at table and circle your plate with your arms,

other people will think              .

         A. you don't like the food

         B. the food isn't good for you

         C. there is something wrong with the food

         D. all the above

2. After finishing dinner, you should            .  

         A. put the fork and knife across the plate

         B. stand up and leave the table

         C. say “I'm full”

         D. say “Thank you”

3. If you want a dish far from you at table, you should           .

         A. stand up and reach across the table for it

         B. leave your seat to get it 

         C. sit there until others help you

         D. ask the nearest person for help

如图所示二杆结构，铰结点C作用铅垂力F，二杆长度均为l，抗拉压刚度均为EA，则利用卡式定理求得C点的铅垂位移为（）。

A.A

B.B

C.C

D.D

可靠性

为什么测定血清中转氨酶活性可以作为肝、心组织损伤的参考指标？

物质M的溶解度曲线如图所示．下列说法正确的是（　　）

A．M的溶解度随温度升高而增大

B．使用降温法可使M从饱和的水溶液中析出

C．在50℃与60℃之间．M在水中的溶解度大致相等

D．在10℃时，将30g物质M放入100g水中，充分搅拌后溶液质量为130g