--- You look unhappy. _____________?--- I lost my watch on my way home.
---______ book do you like best? ---The one on the left.
What will my lovely son be like______?
The silly crow(乌鸦)wanted to______ its song but none would enjoy it.
Mother’s Day makes me______ of my dear mum.
Paris (巴黎) is one of ______ cities in the world.