a silvery malleable metallic element that resists corrosion; used in many alloys and to coat other metals to prevent corrosion; obtained chiefly from cassiterite where it occurs as tin oxide
同义词：tin??/??Sn??/??atomic number 50
The U.N.report notes that the world's poorest countries are also the ones that use the most water for agriculture.
VOA : special.2010.04.05
So, from going from the shell of n equals 2, let's say, to the shell of n equals 3.
比如说，从ｎ等于２到ｎ,等于３壳层如何变化。
化学原理课程节选 : 麻省理工公开课
He urged revival of the slave-trade in the late 1850s, and he developed a theory of what he called warranteeism--w-a-r-r-a-n-t-e-e-I-s-m.
他促成了十八世纪五十年代后期,奴隶交易的复苏,还自己发明了一套理论,名为抵押品主义
美国内战与重建课程节选 : 耶鲁公开课
Gregg Easterbrook writes a weekly piece called "Tuesday Morning Quarterback" for E.S.P.N.com.
VOA : special.2010.02.05
The address is u-s-a-l-e-a-r-n-s dot o-r-g.
VOA : special.2009.01.15
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。