专家为各位考生整理了雅思写作常用词汇：改良/改进供考生们参考使用。
betterment[改良/改进]/improvement
-eg: The betterment of the medical service is what the general public is looking for.;
compulsory education[义务教育]
-eg: 9-year compulsory education;
levy[征税/强加于]/impose
-eg: levy income tax/tax on real-estate.
