用加减消元法解方程组2x+3y=13x-2y=10时，有下列四种变形，正确的是（

这个标志是何含义？

A、大型畜牧场
B、野生动物保护区
C、注意野生动物
D、注意牲畜

情景交际。

1. — Now, where is my purse? 

    — _____! We'll be late for the picnic. [ ]

A. Take your time

B. Don't worry

C. Take it easy

D. Come on

2. — You couldn't have chosen any gift better for me.

    — _____.  [ ]

A. I'm glad you like it so much

B. That's all right

C. Oh, don't you like it?

D. Sorry, I'll choose a better one next time

3. — Micky! 

    — _____, Mum? 

    — Come and help me move the table out. [ ]

A. What

B. Right

C. Yes

D. Pardon

4. — Do you mind if I turned the TV down? 

    — _____. [ ]

A. Yes, I don't mind

B. No, go right ahead

C. Yes, please turn it down

D. Don't worry. You'll get used to it soon

5. — She didn't come to school yesterday, did she?

    — _____, though she was not feeling very well. [ ]

A. No, she didn't

B. Yes, she didn't

C. No, she did

D. Yes, she did

特别适合于分离分子量相近而等电点不同的蛋白质组分的区带电泳是（）

A.琼脂糖凝胶电泳

B.等电聚焦电泳

C.毛细管电泳

D.醋酸纤维素薄膜电泳

E.凝胶电泳

同为封建礼教的牺牲品，梅和鸣凤的个性又有差异，试比较两个人的个性有什么差异？

使用“换箱法”，营业终了，各当班柜员现金零包各币种限额必须在折合人民币（）元以下。

A.5千

B.1万

C.2万

D.10万