1)当直接宾语是人称代词(it/them)时.如：This book is Mr Wang's. Please give it to him. 2)当强调间接宾语时.如：Mother cooks meals for us every day. 3)当间接宾语比直接宾语长一些时.如：On the bus, she often gives her seat to the old person. 3、由to引出间接宾语的动词有：give, show, pass, lend, take, tell等；由for引出间接宾语的动词有：buy, make, cook, get, sing, read等.
