【正确答案】：
THE DIFFERENCES BETWEEN SYNONYMS BOIL DOWN TO THREE AREAS: DENOTATION, CONNOTATION, AND APPLICATION.
DIFFERENCE IN DENOTATION: SYNONYMS MAY DIFFER IN DEGREE OF INTENSITY, TAKE RICH AND WEALTHY FOR EXAMPLE. A RICH MAN AND A WEALTHY LADY ARE BOTH RICH, BUT THE WEALTHY LADY IS FELT TO POSSESS MORE MONEY AND PROPERTY THAN A RICH MAN. 
DIFFERENCE IN CONNOTATION: BY CONNOTATION WE MEAN THE STYLISTIC AND EMOTIVE COLOURING OF WORDS. ASK IS STYLISTICALLY NEUTRAL, BEG IS OFTEN USED IN CONVERSATIONS AND REQUEST IS QUITE FORMAL IN STYLE.
DIFFERENCE IN APPLICATION: MANY WORDS ARE SYNONYMOUS IN MEANING BUT DIFFERENT IN USAGE IN SIMPLE TERMS.  ALLOW AND LET ARE SYNONYMS, BUT WE ALLOW SB TO DO STH AND LET SB DO STH.
【题目解析】：同义词的区别可以归结为三个方面:外延、内涵和应用。外延的区别：同义词的强弱程度上可能不同，以rich和wealthy为例。rich和wealthy都表示富有，但人们认为wealthy lady(女富人)比rich man(富翁)拥有更多的金钱和财产。内涵的差异：我们所说的内涵是指文字的语体和情感色彩。Ask在风格上是中性的，beg常用于口语体，request在风格上比较正式。应用上的差异：许多词在意义上是同义的，但用法并不同。allow and let是同义词，但是常见的搭配是allow sb. to do sth和 let sb. do sth。