1. He was an irresponsible young man.
2. It was a very regrettable incident.
3. This job is incompatible with that one.
4. These books are unsaleable as they are.
5. A boastful young man accompanied her.
6. He was a cruel and implacable dictator.
7. He found himself facing a very precocious young boy.
8. I find that running is a strenuous exercise.
9. That man is unique. He is inimitable.
10. It was a pitiable sight that was offered in front of our eyes.
11. That is just the word. It is very appropriate.
12. The two girls were intimate friends.
13. The two families were irreconcilable enemies.
14. All the pupils are at the same level.
is. This machine doesn't work well. It is defective.
16. In this department you will find miscellaneous works.
17. This is a very lucrative business.
18. Some words in this dialect are unpronounceable.
19. It was a very ingenious watering system.
20. It was a deliberate action.
21. Everything he said was fallacious.
22. All his clothes were impeccable.
23. It's impossible to put it into practice. It's impracticable.
24. I find it exceedingly obnoxious.
25. He is a real moaner/grumbler.
26. It is inconceivable that this may have happened.
27. It was a very lucrative business.
28. Alison is a naive person with a susceptible nature.
29. And such is the inexorable march of progress.
30. He had an unshakeable conviction in the project.
31. We are receiving some extraneous interference.
32. She is a presumptuous and conceited young woman.
33. I'm afraid that your argument is not very plausible.
34. He was an arrogant, supercilious young man.
35. They spread around some malicious gossip.
36. They thought of a very elaborate plan.
37. They lived in a very desolate place.
38. We had very changeable weather.
39. This person is very honest and truthful.
40. I'm afraid that itsn't a roadworthy car.
Sorry, there are small pauses in some of the sentences.