发动机的压缩比是汽缸工作容积与燃烧容积的比值。
参考答案:错
The famous writer______one new book in the past two years.[ ]
A. is writing
B. was writing
C. wrote
D. has written
SO3具有强吸水性,接触湿空气后生成白雾,其主要成分是()。
A.盐酸
B.磺酸
C.硫酸
D.醋酸