1 to use

2 to employ

3 to apply

4 to make use of

1 to use

2 to employ

3 to have to

4 to eat or drink

5 expense or outlay

6 usefulness

7 hence

8 therefore

1 need not

1 surname Cheng

1 attendant on an airplane, train, boat etc

1 to do two things at once (idiom)

2 to multitask

3 to divide one's attention

1 to take advantage of sb in an unguarded moment (idiom)

2 to take sb by surprise

1 to enter by exploiting a weak spot (idiom); to take advantage of a lapse

1 to brave the wind and the billows (idiom); to have high ambitions

1 to have an ulterior motive (idiom)