His uncle _____ until he was thirty-five

You don’t forget when we borrowed that reference book, do you?— I can’t remember now but ________ sometime last week?

He was ________ boy.

Jack, this is the third time that you have been late this week. —Sorry, sir, but I was ____ for 15 minutes on the way here in the traffic jam.

There are several research centers in China ________ a certain disease called Bird Flu is being studied.