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问题 多选题

回旋加速器是加速带电粒子的装置，其核心部分是分别与高频交流电极相连接的两个D形金属盒，两盒间的狭缝中形成的周期性变化的电场，使粒子在通过狭缝时都能得到加速，两D形金属盒处于垂直于盒底的匀强磁场中，如图所示，要增大带电粒子射出时的动能，则下列说法中正确的是（　　）

A．增大磁场的磁感应强度

B．增大匀强电场间的加速电压

C．增大D形金属盒的半径

D．减小狭缝间的距离

答案

AC

填空题

用所给单词的适当形式填空。

1. It's not easy__________(be) the new kid at school.  

2. Thanks very much for__________ (invite) me to your house last night.  

3.I don't feel like__________ (eat) anything today. 

4. My grandmother is going to have her__________(ninety) birthday party.  

5. He always makes things much__________(easy) to do.  

6. Why don't you__________(get) her a nice scarf as a birthday present?  

7. I think the watch as a birthday present is too__________(person).  

8. This is perhaps the best gift that I have ever__________(receive).  

9. This skirt, is too big.  Would you mind showing me a__________(small) one? 

10.I tend to get__________(annoy) when someone interrupts me while I'm having a pleasant  talk with

others.
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多项选择题

发出存货按先进先出法计价与加权平均法相比，其不同的地方在于( )。

A．发出存货的成本比较接近于重置成本

B．物价上涨时，避免虚增利润

C．发出存货的成本与其重置成本差额较大

D．期末结存数额比较接近实际
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