英语俗语所言：
do not write so that your words may be undetstood, but write so that your words must be understood.
著名美国作家马克?吐温说：“用词准确与用词几乎准确，这两者之间的差异就如闪电与萤火虫之间的差异。”(the difference between the right word and the almost-right word is as great as that between lighting and the lighting bug．)
为了择语准确，必须熟悉词语的多义性。例如depression对心理学家、经济学家或地质学家来说，含义各不相同：
he is in a state of deep depression as a result of his setback latest experiment.
the depression first hit almost all the small and medium-sized enterprises.
transportation was at a standstill caused by the depressions in the highways after the earthquake in that area.
反之，也常常有几个词语可以表示类似的含义，如心理学上的“depression”也能用melancholia，the blues，the dismal in the dumps，low等词语表示。
要做到准确选择，有必要注意词语的两种意义：“基本意义”(denotation)和"引申意义"(connotation)。前者指该词语的本身，或客观的固有含义，后者指该词语在一定搭配或上下句中出现的其他意义，往往比较含蓄，带有词语使用者的主观态度或感情色彩。如inexpensive和cheap都表示便宜的基本意思，如顾客问营业员：“may i have some thing cheaper?”意思是希望要价钱便宜一点的，当然并不是说质量可以不好，但cheap