It's worth while 后面是to do 还是doing

worth while只做表语,即跟在be动词、联系动词（be,become,appear,seem等）之后,所以当然前面要加be了~
用法：be worth while doing sthbe worth while to do sth
例句：It’s worth while reading this story.
It is worth while to read this story.（两句同义）

worthwhile是一个词”值得的”应该用：It is worthwhile to do sth.
例：It is worthwhile to read this book.
读这本书是值得的．

This book is worth reading.
This book is worthy of reading.
It is worthwhile to read this book.

This book is worth reading.This book is worthy of reading.This book is worthy to be read.It is worth while to read this book.This book is worth while reading.