The diode consists of a tungsten filament, which gives off electrons when it is heated, and a plate toward which the electrons migrate when the field is in the right direction.二极管由一根钨丝和一块极板组成：钨丝受热时放出电子，当电场方向为正时，这些电子便向极板移动。

Objectionable hydrogen sulfide is removed from such a gas or form naturally occurring hydrocarbon gases by washing with various alkaline solutions in which it is absorbed.
要从这样的煤气或天然存在的烃类气体中除去有害物质硫化氢。

就要用能吸收硫化氢的各种碱性溶液来洗涤．
作业：翻译，注意定语的译法
Over a period of more than 400 million year, trees have evolved as the tallest, most massive, and longest lived organisms ever to inhabit the Earth.
Introducing the table which gives the correspondence of volumes and system numbers with divisions and classes and applying the classification thus determined to find out the appropriate volume.
作业：翻译，注意被动语态的译法
Everying in the world is built up from atoms.
No work can be done without energy.
Evaporation is conducted by vaporizing a portion of the solvent to produce a concentrated solution or thick liquor.
作业：翻译，指明词序的转变
Two widely used alloy of copper are brase and bronze.
Having been well insulated, the wire may be used as a conductor.
作业：翻译，并指明黑字体句子成分转换的译法
Sodium is very active chemically.
Methane is less than half as heavy as water.
The different hydrocarbons in crude oil boil at different temperatures.
作业：翻译，并指明黑字体词类转换的译法
Scientists are confident that all matter is indestructible.
Many chemical reactions need heat to make them take place.
Machine parts of irregular shape can be washed very clean by ultrasonic.
The expression of the relation between force, mass and acceleration is as follows.
He is a stranger to the operation of the electronic computer.
Generally speaking, methane series are rather inert.
One of the outstanding properties of carbon atom is its ability to share its electrons with other carbon atoms.
作业
抄写常用缀和根
翻译如下词的含义
Chlorine，Nitrogen，Oxygen ammonium salt，unsaturated hydrocarbon sodium iodide，aldehyde fractionating column，volumetric flask。