—Mum, where are my new socks?— How _______ I know? You’d better not put your things everywhere.
He hurried out and ______the chair.
There were signs here and there, _____ visitors to look out for ______ rocks.
I don't doubt ______ he will pass the tomorrow’s exam.
We were ______ on our way to the airport because of the heavy snow.
______ all the required papers, he didn’t answer the questions fluently in class.