Human facial expressions differ from those of animals in the degree ______ they can be controlled on purpose.
On Christmas Day, children had _____ singing, dancing and playing games.
______ when he was young, he would have a good job now.
______the most famous musician in the world, he earns a lot of money every year.
_______his homework, he was not allowed to play out.
Who is going to ______ the lecture to be held on Sunday?