Word formation

Question 1

That was a very
(…)
meal: very tasty and filling!
satisfy

Answer 1

satisfying

Question 2

4. The modernisation of the factory will be a very
   (…)
   exercise but vital for the employment situation in this town.
   cost

Answer 2

costly

Question 3

1. Walk on for about half a mile and when you see the
   (…)
   in the forest
   clear

Answer 3

clearness

Question 4

2. I don’t know why I rang you so late. I just had this strong
   (…)
   to speak to you.
   compel

Answer 4

compulsion