下列有关泵说法正确的是（）。A、泵只能在工作点下工作 B、泵的设计点即泵在指定管路上
题型：单项选择题
问题：
下列有关泵说法正确的是（）。
A、泵只能在工作点下工作
B、泵的设计点即泵在指定管路上的工作点
C、管路的扬程和流量取决于泵的扬程和流量
D、改变离心泵工作点的常用方法是改变转速
题型：单项选择题
阅读理解
Many different kinds of birds can copy(模仿) the sound of language. African parrots(鹦鹉)
are the birds well-known for this.
Every December in London, the Bird Show tries to find the best "talking" in the world. One
bird named Prudle stood out among the "talking birds". She was the winner f
or 12 years. Prudle
was taken from Africa in 1958. A man called Iris Frost in England bought her. Prudle was also the
oldest bird in the world that lived in a cage(笼子). Iris Frost looked after Prudle until Prudle died
in 1994. Prudle was 35 years old.
A different kind of bird, not a parrot, named Puck was tested in 1993. People found that Puck
knew more English words than Prudle did. He knew more than 1700 words.
1. What kind of birds usually speak best?
A. African parrots
B. The Bird Show
C. Birds found in the zoos
D. English parrots
2. What is Prudle?
A. A prize
B. A cage
C. A bird
D. A test
3. How many years did Prudle win the speaking contest(竞赛) for birds?
A. twelve
B. thirty-five
C. forty-seven
D. thirty-six
4. Why was Puck better than Prudle?
A. He was bigger.
B. He spoke faster.
C. He knew more words.
D. He was younger.
5. How many words did Puck know?
A. about 1600
B. more than 1700
C. less than 1700
D. more than 1600