Unit 1 Ⅰ Scientific Reading:Welding Ⅱ Access to Scientific English Ⅲ Semi-Scientific Word Study ⑴Negligible,Considerable,Substanteal ⑵Melt,Molten,Smelt ⑶Property ⑷Bring about,Produce,Cause,Give rise to ⑸Critical ⑹Conducive Ⅳ ⑴Maximum and Minimum ⑵Contents Ⅴ Supplementary Readings and Exercises Reading 1 Air Bearings Reading 2 Ozone Depletion and Cancer ……