Earth is believed ______ by an object the size of Mars at some point in the distant past before its surface cooled.
To tell you the truth, I would agree with Shirley, though not ______.
Thanks to the weather satellite, scientists can ____ the weather more accurately.
Today ,I would like to ________my thanks to those who have been supporting me in my life .
David, it’s you ! I could hardly ______ you just now. You have changed a great deal.
It’s ______ trying to persuade him to change his mind because he never listens.