问题 单项选择题

关于螺杆空气压缩机的吸气节流调节说法正确的是()

A.通常在螺杆空气压缩机的吸气管上加装吸气节流阀,利用对吸气的节流,就可实现调节压缩机的容积流量

B.由于节流作用,提高了气体的吸人压力和密度,故理论上可以进行连续无级的调节压缩机的流量

C.当吸气节流时,压缩机的容量在增大,因而其功耗下降

D.当吸气节流时,节流使得吸气压力升高,压比随之升高,单位气量的耗功也随之增加

答案

参考答案:B

阅读理解

阅读理解。

     LOCATION:

     The Farm Park is situated just off the A338, 9 miles north of Salisbury. Look for the brown tourist sign on the A338 and the A303. Ignore signs for East Cholderton.

     OPENING TIME:

     We are open every day from the end of March (or Easter if earlier) until the end of the Autumn Half

Term (about the  end of October) from 10 am until 6 pm, last admission 4:45 pm. (NOTE: No

unaccompanied children admitted)

     PARKING:

     A free car and coach park is available.

     DOGS:

     Dogs may be brought into the park provided that they are kept on a lead and under control at all times.

     CAFETERIA:

     There is a cafeteria in the farm house serving hot meals and snacks. Clotted cream tea is a specialty.

Parties are catered for if booked in advance.

     CHILDREN'S PLAY AREAS:

     An adventure playground is located in part of the wood and an under 7's play area is to be found near Rabbit World. A parent and baby room is available for feeding and changing.

     ANIMAL FEEDING:

     Bags of animal food are available for sale in the gift shop. Please do not feed any other food to any of

the animals without permission. Do not feed the fish.

     TRACTOR & TRAILER RIDES:

     These are available during peak times (see information board at Rabbit World) at a small additional

charge.

     EDUCATION:

School groups are welcome, a special entrance rate is available, also a comprehensive teachers pack.

     PARTY RATES:

     Reduced admission charges are available to group of fifteen or more when booked in advance. Details on request.

     SEASON TICKETS:

     Season tickets are good value for regular visitors and last the whole season (March~October)

     DISABLED VISITORS:

     Disabled visitors are welcome, a specially adapted toilet is available and the majority of the park is

accessible.

1. What do you think this text is?

A. An advertisement for sale.

B. A brief introduction of an animal park.

C. An announcement of the park owner.

D. A lecture about an animal park.

2. Who are allowed to enter the park?

A. Those who arrive at 5 pm.

B. The children without anyone to accompany.

C. The visitors who come during the Christmas holidays.

D. The people with disabilities.

3. Which of the following statements is true?

A. Visitors can feed the animals except fish with permission.

B. Dogs are not allowed in at all.

C. In the park visitors can't be served with hot meals.

D. Tractor & trailer rides are free.

判断题