Tom wants to be_______ engineer when he _________up.
Don’t get off the bus __________ it stops.
--How long ________ you _________ this book? --For about one week. I ________ it from the library last Tuesday.
---Has he returned from Canada_________? --- Yes, he’s _________ come back.
--Where is Mr. Smith? ---He ___ Guangzhou. He ____ there for a week.
My grandpa _____ in the city , but now he______ the life in the country.