2017航海英语复习六Key word 20: Humidity and Dew point（8）B783.Humidity is known as the amount of in the air.A. hydrogenB. moistureC. dustD. temperature【知识点】湿度【解析】湿度是指空气中水分的含量。
C750、Relative humidity is defined as __________A. the maximum vapor content the air is capable of holdingB. the minimum vapor content the air is capable of holdingC. the ratio of the actual vapor content at the current temperature to the air‟s vapor holding capabilityD. the ratio of the moisture content of the air to barometric pressure【知识点】相对湿度【解析】相对湿度定义为特定温度下空气中实际水汽含量与饱和含量之间的比值。
相关题目B751、________is the actual amount of water vapor in the air compared with the saturation amount of water vapor in the air at the same temperature and pressure, the figure is usually expressed as a percentage, with saturated air having a relative humidity of 100%.A. dew point temperatureB. relative humidityC. saturated humidityD. humidityB716、Relative humidity is the percentage of water vapor that is in the air as compared to the maximum amount it can hold at ______.A. a specific barometric pressureB. a specific temperatureC. a specific wind speedD. any timeA682. The expression “the air is saturated” means __.A. the relative humidity is 100%B. the vapor pressure is at its minimum for the prevailing temperatureC. precipitation has commencedD. cloud cover is 100%【知识点】相对湿度【解析】空气饱和是指相对湿度为100%。
D681.The dew point is reached when the ___A. temperature of the air equals the temperature of the seawaterB. atmospheric pressure is 14.7lbs. per square inchC. relative humidity reaches 50%D. air becomes saturated with water vapor【知识点】露点【解析】空气中水汽饱和时，刚好达到露点温度。
（气压一定）D664. As the temperature for a given mass of air increases, the ______.A. dew point increasesB. dew point decreasesC. relative humidity increasesD. relative humidity decreases【知识点】露点与相对湿度【解析】给定气团的温度升高时，相对湿度减小。
D676. A heated bulkhead has the effect on a hygroscopic commodity of ______.A. causing moisture to accumulate against the bulkheadB. lowering the vapor pressure of the commodityC. lowering the dew point of the airD. raising the vapor pressure of the commodity【知识点】货物照管——相对湿度与露点【解析】hygroscopic commodity 吸湿性货物Key word 21: Fog and visibility （9）D649. The fog produced by warm moist air passing over a cold surface is called_____.A. conduction fogB. radiation fogC. frontal fogD. advection fog【知识点】平流雾【解析】暖湿空气经过较冷的下垫面形成的雾是平流雾。
conduction 传导；radiation fog 辐射雾；frontal fog 锋面雾；advection fog 平流雾相关题目D720、The fog most commonly encountered at sea is called _________A. conduction fogB. radiation fogC. frontal fogD. advection fogD633. Advection fog is most commonly caused by ______.A. air being warmed above the dew pointB. saturation of cold air by rainC. a rapid cooling of the air near the surface of the Earth at nightD. warm moist air being blown over a colder surfaceB775. The passage of very cold air over much warmer water causes _________A. frontal fogB. arctic sea smokeC. advection fogD. radiation fog【知识点】蒸汽雾【解析】很冷的空气覆盖在暖海面上会形成“北冰洋蒸汽雾”。
寒冷稳定的空气覆盖在暖海面上，海面蒸发使贴近海面的空气达到饱和形成雾，称为蒸汽雾（steam fog）。
多产生于极地冰原的边缘、冰间水面、亚洲和北美的东海岸。
D749、The degree of being seen under certain weather condition is called _________A. frontB. depressionC. swellD. visibility【知识点】能见度【解析】特定天气条件下的能见距离称为能见度。
B754、When visibility is 10 nautical miles, we say that visibility is ___________A. very goodB. goodC. poorD. moderate【知识点】能见度的等级【解析】能见度为10海里，等级为良好。
相关题目A160. During this season each year, the visibility in the abovementioned area is ____.A. poorB. smallC. littleD. trifleA748. ______will reduce the visibility．A.dust B．sea water C．land sand D．WindB781.Visibility at sea can not be affected by ．A. RainB. darkC. snowD. hailKey word 22: Cloud （6）A636. Cloud formations are minimal when the ______.A. surface temperature and temperature aloft are equalB. surface temperature and temperature aloft differ greatlyC. barometric pressure is very lowD. relative humidity is very high【知识点】云形成的条件【解析】上升运动+水汽→云形成C638. Clouds are classified according to their ______.A. sizeB. moisture contentC. altitude and how they were formedD. location in a front【知识点】云的分类【解析】云根据其高度和成因分类。
D627. A cloud of marked vertical development (often anvil-shaped) would be classified as ______.A. cirrusB. cirrocumulusC. altocumulusD. Cumulonimbus【知识点】云的分类【解析】垂直发展、呈砧状——积雨云D639. Clouds that form as small white flakes or scaly globular masses covering either small or large portions of the sky are ______.A. cirrusB. cirrostratusC. altostratusD. cirrocumulus【知识点】云的分类【解析】形状呈白色小薄片或球状鳞片，小范围或大面积的出现在天上——卷积云。