I gave Jim a book yesterday. (变为被动语态)
A book was given to Jim by me yesterday.
Jim was given a book by me yesterday.
变被动时什么时候+to什么时候不加呢?
请英语语法网参考:
http://www.yygrammar.com/Article/201501/3788.html
http://www.yygrammar.com/Article/200909/1355.html