某一活塞式空气压缩机将1m3。空气由105Pa压缩至27×105Pa,其最佳压力比ε0为3,则级数I为()。
A.1
B.2
C.3
D.4
参考答案:C
解析:
[题解]
句型转换。
1. The elephant likes water. (改为否定句)
The elephant _____ _____ water.
2. The panda eats bamboo. (改为一般疑问句, 并作肯定回答)
_____ the panda _____ bamboo?
Yes, _____ _____ .
3. The kangaroo comes from Australia. (改为同义句)
The kangaroo_____ _____ Australia.
4. The zoo has five thousand animals. (改为同义句)
_____ _____ five thousand animals in the zoo.
5. I live in China and I speak Chinese. (改为用she作主语)
She _____ in China and she _____ Chinese.
下列各项,属于魏晋时期矿冶技术进步的是:()
①制造军刀技艺高超
②百炼钢技术相当成熟
③发明了灌钢法
④出现了谢平、黄文庆两位中国绝手
A、①③
B、②④
C、②③
D、①④