My deskmate exercises regularly every day,so he is always________and studies efficiently.
By the time he was ten, Edison _________ experiments in chemistry.
The businessperson wanted to sell his goods fast; ______, he chose his partner with great care.
Do you know the man____ is talking with Tom?
A dictionary is a book ______ gives the meanings of words.
The old town has narrow streets and small houses ________ are built close to each other.