_______ made the parents proud was________ their son had been admitted to a key university.
It was _________ to everybody that he was angry.
Whenever I get into trouble, I always _______ Peter.
At minus 130℃, a living cell can be _________ for a thousand year.
Earth is believed ______ by an object the size of Mars at some point in the distant past before itssurface cooled.
our earth, or else it will be no longer fit for us to live on.