4. 大多數(shù)人都熟悉這樣一個概念，物質(zhì)是由叫做原子的極小粒子組成的。

　　Most people are familiar with the idea that matter consists of very small particles called atoms.

　　5. 一星期由七天組成。

　　A week consist of seven days.

　　6. 混合物由兩種或更多彼此不發(fā)生化學(xué)合成并能被分開的物質(zhì)組成的合成物

　　A composition of two or more substances that are not chemically combined with each other and are capable of being separated.

　　7. 馬氏本，馬登斯體一種由鐵和高達(dá)百分之一的碳組成的溶液，是硬化碳工具鋼的主要成分。

　　A solid solution of iron and up to 1 percent of carbon, the chief constituent of hardened carbon tool steels.

　　8. 鑒于稅務(wù)原因，我們得組成公司。

　　We had to incorporate for a company for tax reasons.