E-Commerce ______ mislead customers at times even though it's more convenient and faster in general.

This book _______ be Tom’s. Look! His name is on the cover.

I told Sally how to get here, but perhaps I ___ for her.

 My English-Chinese dictionary isn’t in my schoolbag. Where _________ I have put it?

—Look! That man looks like Mr．Brown．—It ________ be him, for I know he is at home．