18. An advertisement should regularly appear on only one form of media to make more influence on customers.
Correction: An advertisement should regularly appear on multiple forms of media to have a greater influence on customers.
17. A successful advertisement is the one that can persuade the customers to buy the product.
Correction: No correction needed.
19. Factual appeal aims at making the customers believe that the product being advertised is the best.
Correction: Factual appeal aims at providing information about how the product is made or works to convince customers.
20. A slogan should be brief and easy to remember.
Correction: No correction needed.
21. A. brought
Correction: No context is provided for this question, so no correction can be made.
22. A, moment
Correction: A. moment
23. A, activity
Correction: B. activity
24. A. which
Correction: B. that
25. A. completely
Correction: B. becoming
26. A. violent
Correction: C. cruel
27.A. on
Correction: C. in
28. A. point
Correction: C. say
30. You must always tell the truth.
31. He is true to everyone, so he has got few friends.
29. She can find no solution to her financial troubles.
32. Those foreigners spoke so fast that I couldn't understand them.
33. It is a difficult choice to make.
34. Why don't you use this old table? It's heavy.