Since then the population of London________by almost 50,000 a year—an increase largely fuelled by immigration.

—That must have been a lot of work.—Yeah, it ________ us three days to finish it.

--- An ant has two stomachs --- one for itself, one for others.--- Really? Quite interesting. I ____ anything about it.

My father and my mother have been married for 30 years, and never once ______ with each other.

---Where have you been recently? --- I _______ in Hangzhou on business for a week last month.