Which of the following words is entirely arbitrary? AtreeBtypewriterCc

Which of the following words is entirely arbitrary?

tree

typewriter

crash

bang

答案及解析：本题考查语言的任意性特征。A选项，tree的形成比较任意，综上，A选项正确。B选项，typewriter是复合词，并非任意，不合题意，故排除。C选项，crash是一个缩略语，Citizens for Reliable and Safety Highways，安全可靠、公民高速公路并非任意，不合题意，故排除。D选项，bang是拟声词，并非任意，不合题意，故排除。故正确答案为A。