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问题 选择题

下列哪条抛物线向左平移两个单位，再向上平移一个单位，可得到抛物线y=x2（　　）

A．y=（x-2）2+1

B．y=（x-2）2-1

C．y=（x+2）2+1

D．y=（x+2）2-1

答案

抛物线y=（x-2）2-1向左平移两个单位，再向上平移一个单位得：y=x2．

故选B．

填空题

单词拼写。

用括号中所给单词的适当形式填空。

1. The____ is physically stronger than the female.( female)

2. It's ___ to carry guns in our country. (legal)

3. Her decision seems to show a lack of political____.(judge)

4. Tim's drinking has made him on____ to his family. ( embarrass)

5. He had no sense of____ and never felt guilty.( ashamed)

6. It took us a few minutes to get our ____back after the race. ( breathless)

7. His___ to drugs pushed him towards a life of crime. ( addicted)

8. I wasn't informed of the____ until too late.( decide)

9. It's____ for the boy to eat so much.( normal)

10. She's a bit too knowing for me to feel____ with her.( relax)

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单项选择题

承受相同扭矩且长度相等的直径为d1的实心圆轴与内、外径分别为d2、D2 ()的空心圆轴，二者横截面上的最大切应力相等。二者质量之比(w1/W2)为（）。

A．A

B．B

C．C

D．D
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