Mandarin equivalent of 返 in Cantonese? Is it 回? In Cantonese, one of the ways 返 is used is to express "return" or "back". What word in Mandarin is the best equivalent to it? Would it be 回?

Here are the examples - not sure if the translation is correct. 

Ex. 我要還返本書俾佢 -> 我要还回本书给他 (I need to return a book to him)

Ex. 走之前記住攞返鎖匙 -> 走之前记住拿回钥匙 (before you leave, remember to get your keys)

Thanks for any help.
As a verb particle, the Mandarin equivalent of 返 in Cantonese is indeed 回

俾返你一啲好處(C) = 給回你一點好處 (M) = give you back some benefit 

Edit:


First, the term 還返 is uniquely Cantonese, "我要還返本書俾佢" in Mandarin would just be "我要还本书给他". 
Second, 本 is a classifier without determiner or count word, it  is normal in Cantonese, but in Mandarin, you should not omit the determiner or count word; you should write "我要还(這)本书给他" or "我要还(一)本书给他" 
Finally, you can omit the classifier along with the determiner and write "我要還書俾佢" / "我要还书给他