高考必背英语词汇讲座 M4

容。常用短语：a question of substance 实质性问题；have substance 有道理，有根据，有内容。The function of the root of a plant is to fix the plant in its place and to take in water and food substance present in the earth.植物根的功能是将植物固定在所处的位置，并从土壤中吸收水及营养物质。A good chemical laboratory is equipped with precision instruments and supplies of many chemical substances. 一个好的化学实验室应配有精密仪器，并有充足的各种化学物质供应。　
4、maybe, possibly, perhaps, probably
　　这四个词都可表示“可能性”。
　　maybe：“可能，也许”，比其余的几个词更为随便和不正式，可能性不大，也可以表示一种非常委婉,礼貌的建议或要求。如：You could put it over there, maybe. 也许你可以把它搁在那边。He didn't feel quite right; maybe he got sunstroke. 他觉得不太好；也许是有点中暑。The doctor thinks maybe we'd better have a minor operation. 医生认为也许我们做个小手术。
　　possibly：“可能地，或者，也许"，可能性较大。用于否定句和疑问句时表示 "无论如何"之意。She expressed regret for any inconvenience which might possibly be caused.她为任何可能造成的不便而深表歉意。I couldn't possibly have finished typing such a long document in such a limited period of time. 无论如何，我也不可能在如此有限的时间内打完这么长的文件。