选worthwhileworth, worthy, worthwhile在用法上的区别是:worth是介词, 后接动名词或名词,形成介词短语。接动名词时, 与主语是动宾关系,其形式是主动的,意义是被动的。如: The book is worth reading. worthy是形容词, 置于be动词后或名词后面, 做后位修饰语, 其结构是: be worthy of doing sth., sth. is worthy to be done。worthwhile是形容词,要与形式主语it并用:It is worthwhile to read the book.worth和worthy都不能用于这种结构。