The country life he was used to ____ greatly in the past decade． 

Being a teacher always encouraging students to think for themselves, I won't tell them answers until they __________ on a math problem for more than an hour.

He could speak English fluently because he __________ it for four years when he was a college student.    

--- Have you finished the report?
--- No. I ______ it all this week.

— Remember the first time we met, Jim?
— Of course I do. You _______ in the library.

John promised his doctor he ________not smoke，and he has never smoked ever since.

—Time ________. It’s likely that we’ll miss the deadline.
—Don’t worry. We have already got through 80% of the job.

It is the fourth time that she  ________you in a week.

–Tom, what’s the matter with you? You look so worn out!
--Nothing serious. I ____ my new house all the day and I am afraid I won’t finish until tomorrow afternoon.

Rainforests ____ and burned at such a speed that they will disappear from the earth in the near future.