15. It's high time we _____for the event； we don't want to be late.
(A) leave
(B) left
(C) have left
(D) leaving

11. The weather was terrible, so Sarah decided to _____ her plans and stay indoors. (A) cancel (B) cancelled (C) cancelling (D) cancels

12. I can't believe how much the company's profits_____ last year. (A) have increased (B) increasing (C) increased (D) increase

13. If he _____ the train, he would have missed the important meeting. (A) missed (B) would have missed (C) had missed (D) would miss

14. The director presented the annual report, _____ emphasized the center's achievements over the past year. (A) who (B) whom (C) which (D) that

16. By next year, she _____ for this company for ten years. (A) will be working (B) would have worked (C) will have been working (D) would have been working

17. I'm looking forward to _____ you at the conference next week. (A) met (B) meet (C) meeting (D) be meeting

18. Which of the following is correct? (A) So far the manager has interviewed fifty applicants, one of whom has a doctorate degree. (B) Teenagers spend an average of four hours a day on their smartphones, the majority of whom are spent on social media. (C) Over a thousand people, most of which were female, participated in the marathon. (D) On the shelf are over twenty mugs, all of which is designed by the most famous artist in town.

19. Which of the following is NOT correct? (A) Ten dollars is too much to pay for a coffee. (B) Each of the contestants is on the stage waiting. (C) Mathematics has been difficult for me since I was a child. (D) Neither the teacher nor the students wants to leave the house.

20. Which of the following expressions is more correct? (A) Singing at the top of his voice, the song irritated everybody at the party. (B) Stuffed with chestnuts, Peter served the turkey to his family and friends. (C) A decision was finally reached after reviewing all of the facts available. (D) They failed the experiment, not having studied the lab manual carefully.

21. (A) incompatible (B) inevitable (C) inconsequential (D) instructive