前言

In situ combustion is an important method for thermal recovery of viscous oil reservoir,the key of success is sand face ignition.

前言火烧油层是热力开采稠油油藏的重要方法之一。其成功的关键是油层点火。

Copper foil is the key conducting material to the manufacture of PCB.

1前言绝大部分的铜箔被用来制造印制板，它是制造印制板的关键性导电材料[1]。

Taking the horizontal control survey of Qinling Tunnel as an example and on the premise of the survey design,the paper presents in detail the technical points and arrangement methods of the horizontal control survey inside long cut-through tunnels and the concrete requirements and items to which attention should be paid during the survey.

0前言隧道贯通误差在铁路测量规范中有着明确的限差规定，它是衡量隧道正确施工和控制测量精度的重要指标。

Compared with other countries, the death of stroke is serious.

前言 目前，中国与世界其他国家和地区比较，脑卒中的死亡率较高。

This paper deals with the preparation of synthetic diamond single crystal with boron at high temperature and high pressure from Fe-Ni-C-B system.

1前言石墨转变为金刚石是碳的同素异构体转变，由于触媒的参与使之合成压力与温度大幅度降低。

A process of alkaline hard chromium plating on aluminum alloy was presented,including oil removal,dipping in heavy metal solution,acid pickling,dipping in zinc solution,hard chromium plating.

1前言铝合金电镀硬铬，是利用强碱性的锌酸盐溶液在置换锌层上直接镀铬，其工艺成熟，操作简便、易行。

This thesis divides prefaces altogether, introduction,research of the diatomaceous earth, carrying calcining dealing with and purly diatomaceous earth, diatomaceous earth application in modified asphalt , diatomaceous earth among modified pitch modify mechanism probe into function to asphalt and conclusion 6 parts .

本论文共分前言、硅藻土的研究、硅藻土的提纯和煅烧处理、硅藻土在改性沥青中的应用、硅藻土对沥青改性作用的机理探讨和结论六个部分。

Measured positive and negative electrode potential must rely on the reference electrode, to determine its relative value.

前言 Foreword 测量正、负极电极电位要借助参比电极，来确定其相对值。

The president of the National Academy, Bruce Alberts, added this key point in the preface to the panel's report:"Science never has all the answer."

国家科学院的主席Bruce Alberts在会议的报告前言中补充和强调了这一点，即&科学没有所有问题的答案。&

Kevlar 49 is an aromatic polyamide fiber with a high modulus anda high tensile strength, It has become very popular for a variety of applicationranging from body armours to aircraft structuval parts.

一、前言 Kevlar纤维是一种高强度、高模量、低密度、低成本，又具有良好化学稳定性和耐热性的有机纤维。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。