If plastic film insulation becomes damaged in air conditioni

A、involving/ damage

B、involved/ damaged

C、involved/ damage

D、involve/ damaging

A.is good for long term preserving since most insulation is organic and contains some amount

B.lowers the insulation value and is a common cause of fault grounds in idle machines

C.will enhance insulation resistance only if it is no salt

D.reduces the amount of current supplied or drawn by the machine so horsepower is limited

E）任务型阅读（共5小题，计10分）

阅读下面的短文，根据短文内容，完成表格。（每空填1至3个词）

China has decided to stop the use of free plastic bags. Supermarkets， shops and outlets(经销店) in China can’t offer plastic bags any more.

Every year， people use too many plastic bags. They throw them here and there after they have used them. The government has done its best to deal with them but failed. While we offer quick service（服务） to customers， the plastic bags pollute water，earth and air， and they waste the oil. The government asks people to go back to carry cloth bags and use baskets when they go to buy something. The cloth bags and the baskets can be used again and again.

Many months have passed. The environment has been improved a lot.

Action

Make a decision to stop the use of 41.

42.

Supermarkets， shops and outlets

Advantage

Offer43. service to customers

Disadvantage

Pollute water， earth and air and waste44.

What should we do

Go back to carry cloth bags and use 45.

41.__________

A vessel which is being assisted by an icebreaker would display a flag hoist consisting of the code numeral "4" when the vessel ______.

A.speed begins to drop

B.stops

C.receives ice damage

D.becomes icebound

Electric insulation is made of organic substances and so gradually______with age

A.deteriorates

B.increases

C.are fouled

D.becomes better

A.high...thinner

B.higher...thin

C.high...thin

D.higher...thinner

第二组

Under normal operation, some lubrication oil mist may be discharged from the air compressor to the air start system. This oil may be from excess compressor cylinder lubrication, from faulty oil scraper rings, or may even be suspended oil vapor contaminating the engine room atmosphere and drawn in at the compressor suction. Oil discharge is kept to a minimum by draining the after cooler, air receiver and starting system. If small quantities of lubrication oil do get passed into the starting air system, they will deposit as thin moist film over internal pipe surfaces but are not readily combustible. If a cylinder non-return valve leak while the engine is in operation, some hot gas, possibly with unburned fuel and cylinder lubrication oil, may be blown through the valve to the adjacent air manifold. With further heating from the leaky valve, this, together with the already deposited oil film, will carbonize and form. incandescent carbon. If starting air is applied to the system while still hot, the high pressure air coming into contact with the burning carbon may cause an explosion. Such an explosion will cause a flame to pass back through the air start pipe system, evaporating the deposited oil film and igniting it in the presence of air. Very high velocities and shockwaves are generated which may rupture pipes and fittings.

Alternatively, if excessive oil has entered the air start system, a mixture of air and oil droplets may be discharged through the open cylinder non-return valve during starting. This spray may ignite due to high temperatures in the cylinder, causing a flame through the still open valve to the air manifold.

To prevent an explosion, air start valves must be correctly maintained and lubricated to ensure correct timing and free movement with positive closing. Oil in the system must be kept to a minimum, pipe lines must be drained and cleaned internally when necessary and oil discharge from air compressors must be kept to a minimum by good maintenance.

The passage is mainly about

A.crankcase explosion

B.scavenge box fire

C.starting air pipe

D.the danger of explosion in the starting air system

A. the best film I've ever seen

B. a best film I've ever seen

C. the best film I've never seen

D. the best film I've always seen

The dew point is reached when the ______.

A.temperature of the air equals the temperature of the seawater

B.atmospheric pressure is 14.7 lbs. per square inch

C.relative humidity reaches 50%

D.air becomes saturated with water vapor

What should be used to steer an open lifeboat if the rudder becomes lost or damaged ________．

A.Sea anchor

B.Steering oar

C.Spare rudder

D.Daggerboard