大管轮轮机英语综合(33-48期)(6)

140． Which of the following devices may be used to warm the engine prior to starting?

A. A high temperature cooling water system. B. A low temperature cooling water system. C. A central cooler.

D. The second stage cooler. 第二组:

Combustible gases and vapours, such as petroleum vapour, when mixed in the correct proportion with air in an enclosed vessel will burn so rapidly that an explosion occurs. The

burning can be initiated quite easily, ignition often being caused by a relatively small spark. For each gas or vapour there is, however, an upper and lower concentration of vapour in air between which an explosion can occur. These limits are referred to as the lower flammable and upper flammable limits (LFL and UFL) or, alternatively, the lower and upper explosive limits (LEL and UEL). Petroleum vapour for instance, has an LEL of 1.4% and a UEL of 6.4% while hydrogen has an LEL of 4% and a UEL of 75%. Crude oil contains a variety of hydrocarbon mixtures and the vapour contained in crude oil tanks will exhibit a wide variety of upper and lower explosive limits.

141． Which of the following statement is not true?

A. Ignition energy of combustible vapours is small. B. Combustible gases are easily burned.

大管轮轮机英语综合

C. Petroleum vapour can be initiated when the concentration of the vapour in air is between LFL and UFL.

D. There is a wide range of upper and lower explosive limits of crude oil.

142． The flammable range of hydrogen gas is larger than that of petroleum vapour according to

this paragraph, it means _________ . A. hydrogen gas is easier to burn

B. petroleum vapour is easier to ignite C. hydrogen gas is more dangerous D. petroleum vapour is more dangerous

143． The phrase “the correct proportion with air “ means _________.

A. only when the concentration of the mixture is lower than LFL, an explosion occurs B. only when the concentration of the mixture is higher than UFL, an explosion occurs C. only when the concentration of the mixture is within the limits, an explosion occurs D. only when the combustible gases are in air, an explosion occurs 144． The cause of combustible gas explosion is .

A. they burn in an open vessel

B. they burn rapidly in an closed vessel C. they burn due to too much oxygen D. they burn due to lack of oxygen

中华人民共和国海事局

2004年第3期海船船员适任证书全国统考试题(总第35期)

科目：轮机英语 试卷代号：803

适用对象：无限、近洋航区3000KW及以上船舶大管轮

（本试卷卷面总分100分，及格分为70分，考试时间为100分钟）

答题说明：请选择一个最合适的答案，并将该答案按答题卡要求，在其相应位置上用2B铅笔

涂黑。第1题至68题，每题1分，第69题至76题，每题1.5分,第77题至78题, 每题10分。

一、单项选择题：

1. The connecting rod is fitted between the crosshead and the crankshaft. It transmits the firing force,

and together with the crankshaft converts the _____motion to a _____motion. A. rotary/reciprocating B. up and down/fore and aft C. fore and aft /up and down D. up and down/ rotary

2. The purpose of the skirt or trunk in four-stroke cycle engines is to act in a similar manner to

a_____.

A. crosshead B. crown C. piston rod D. connecting rod

3. Additives ______protective layers on metal surfaces guarding them against corrosion.

A. damage B. form C. dissolve D. contaminate

4. ______ less equipment in contact with sea water, the corrosion problems are much reduced in a

central cooling system.

A. Because B. With C. Without D. Though

5. Medium speed engines have a _____power to weight ratio than the slow speed two strokes, but

due to the higher speeds tend to have _____maintenance intervals.

A. higher/reduced B. higher/increased C. lower/reduced D. lower/increased 6. ______ neutralizes the acid conditions and ______cleanses the rings and grooves.

A. The detergency/the alkalinity B. The alkalinity/the detergency C. The inhabitant/ the water D. The additives/the distilled water

7. ______ water is more expensive than fresh water, It has high specific heat and low viscosity.

A. Distilled B. Distilling C. Boiling D. Boiled

8. Charging is the filling of the engine cylinder with a supply or charge of fresh air ______

compression.

A. to need B. ready for C. want to D. going to be

9. Starting air for auxiliary engines may be taken directly from the main reservoirs or

through______.

A. an auxiliary reservoir B. a controlling air bottle C. an emergency air compressor D. a main air compressor 10. ______ is the removal of exhaust gases by blowing in fresh air .

A. Gas exchange B. Charging C. Scavenging D. Supercharging

11. Indications of _____are loss in power and irregular running of the engine, high exhaust

temperatures of corresponding units, high local temperature in scavenge trunk, surging of turbocharger, and sparks and smoke emitted from scavenge drains. A. a crankcase explosion B. a scavenge fire C. abnormal compression ratio D. incorrect air/fuel ratio

12. ______ of the controllable pitch propeller enables the blades to be moved to change the pitch

angle.

A. An external mechanism B. An internal mechanism C. An interlock device D. A hunting gear system 13. ______ the repair in so short a time is unknown to us.

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