问题 问答题

现有四种设备A、B、C、D可供选择,其寿命周期费用依次分别为240万元、220万元、200万元、180万元。生产率依次分别为800吨/日、765吨/日、710吨/日、600吨/日。从系统效率中生产率这一项来比较,选择费用效率最好的。

答案

参考答案:费用效率=系统效率/寿命周期费用
A费用效率=800/240=3.33(吨/日·万元)
B费用效率=765/220=3.48(吨/日·万元)
C费用效率=710/200=3.55(吨/日·万元)
D费用效率=600/180=3.33(吨/日·万元)
选择C方案,因为其费用效率最高。

判断题
阅读理解

阅读理解

Do's and Don'ts in Whale(鲸)Watching

     The Department of Fisheries and Oceans has developed guidelines  for  whale  watching  in  Johnstone Strait.where killer whales are found on a daily basis each summer.It is strongly recommended that vessel

operators follow these guidelines for all kinds of whales.

     ●Appmach whales from the side,not from the front or the back.

     ●Approach no closer than 100 metres,then stop the boat but keep the engine on.

     ●Keep  noise  levels  down-no  horns,whistles  or  racing of engines.

     ●Start your boat only after the whales are more than 100 metres from your yessel.

     ● Leave the area slowly , gradually moving faster when you are more than 300 metres from the whales.

     ●Approach and leave slowly , avoiding sudden changes in speed or direction.

     ●Avoid disturbing groups of resting whales.

     ●Keep at low speeds and remain in the same direction if travelling side by side with whales.

     ●When whales are travelling close to shore, avoid crowding them near the shore or coming between

the whales and the shore.

     ●Limit the time spent with any group of whales to less than 30 minutes at a time when within 100 to

200 metres of whales.

    ●If there is more than one vessel at the same observation spot,be sure to avoid any boat position that

would result in surrounding the whales.

    ●Work together by communicating with other vessels , and make sure that all operators are aware of

the whale watching guidelines.

1. For whom is this text written?_________

A. Tour guides.            

B. Whale watchers.

C. Vessel operators.      

D. Govemment officials.

2. When leaving the observation areas, the vessel should________.    

A. move close to the beach

B. increase speed gradually

C. keep its engine running slowly

D. remain at the back of the whales

3. When going side by side with whales, the vessel should_______.

A. keep moving in the same direction

B. surround the whales with other boats

C. travel closer and closer to the shore

D. take a good viewing position

4. What is the shortest safe distance from the whales?_______   

A. 400 metres.                

B. 300 metres.

C. 200 metres.              

D. 100 metres.