.--- Where did he leave his car key? --- It was in the lab he made the experiment.
—Would you please help me to send her the book at your ___? —Certainly
He ___ estimated the cost of the product and found that it might cost 10,000dollars or so.
___ to accept his offer, she politely said that she could manage it by herself.
To ___ the puzzlement of the students, the teacher explained it once again to them.
___ the smell of the meat, the dog ran into the room very quickly.