A new __________to teaching English, is being used here, and it has proven to be very helpful to the students. 

I can remember very few ____ when he had to cancel his plans because of poor health．

As a heavy smoker , he finds it hard to get rid of the habit, which has a bad _____on his health.

The country’s 　　　is based on trade.

I bought a dress for only 10 dollars in a sale;it was a real _________.