New technology ______ to make sure that the cars, taxis, buses and trains we use ______ the air.

 The suit _____ over60 dollars.

Is this the first time that you _____ here?

— When will you come to see me, Dad ?— I will go to see you when you _____ the training course. 

The black box is a necessary device on an airplane, which records its speed, direction and whether everything on the airplane______ normally.