---How often do you drop your e-pal a line?---_______, but usually once a week.
He felt his chair ___ at the time of the earthquake.
The dictionary doesn't belong to your brother ____, but it belongs to me.
People __ her because she ___ such a strange hat.
--Do you know the man ___ John Brown? ---I only know ___ he is called.
___ we know, in a chemical change, energy cannot be created, ____.