I didn’t have to work all weekend — I did it by _______. 

Those should be a total    on smoking in office for our health.

—Do I need to give a tip if I eat at a fast food restaurant in the United States? —Yes, it’s a common ______ to tip waiter in a restaurant.

--- Mum, I’m going to visit my aunt. What about a week? --- A week is too long. Try to be back in a ______ of days. 

.---How long did Mary work here?---For half a year, but she didn’t leave us much ____. We hardly remember what she is like.