Here are the correct answers for each question:

18. She is intelligent; **B. however**, she is humble.
19. You **A. must** finish your homework before you go out.
20. The team, along with their coach, **C. has** practiced for weeks.
21. **A. Swimming** is my favorite sport.
22. You **D. will** try your best in every situation.
23. She likes **B. singing** in the shower.
24. She had studied hard, **D. yet** she couldn't answer the difficult question.
25. Students **C. might** be quiet in the library.
26. The news, as well as the updates, **A. is** on the website.
27. You **D. must** complete the assignment by tomorrow.