17. I'm still confused in solving mathematic problems. The word confused means ... a. Unable to think clearly b. unable to perform well cunable to behave politely d. Unable to speak fluently e unable to read quickly 18. I'm just worried that I fail the national examination. The antonym of word fail is a. escape b. predict csuccess d. reach e underestimate 19. If you want to ask for a help in your letter what will you say? a. I am sorry that.. b. I am sorry to tell you that... c. I wonder if you could help me d. I think you shouldn't e I'm sure you'll be happy to hear that. 20. Below are the expressions of gratitude, except.. a. I'm just writing to thank you for... b. It was kind of you to c. Thank you very much for... d. I'm very grateful for... e I would like to apologize for...​