On entering the office, I found Mr. Thompson _____ at the desk and _____ something.
David is such a good boy _______ all the teachers like.
______ is mentioned above that the number of the students in senior school is increasing.
_____ is mentioned above, the number of the students in senior school is increasing.
_______ is known to everybody that the moon travels round the earth once every month.
____ is known to everybody, the moon travels round the earth once every month.