You don’t know ________ I want to see you again. It’s years since I saw you last time.
— I didn’t know you were friends with Mr. Smith. — We ______ each other for6 years.
When I was a boy, I often ______ to play in that park.
— ______ do you go to the gym? — Once a week.
Nowadays it’s very useful ______ a foreign language.
His English is as ______ as his Chinese.