15. C - visiting là HTPT dạng Ving
16. B - to enrich
-> to Vnt chỉ mục đích
18. B - conserving
-> care Ving
19. A - giving
-> would you mind Ving
20. B - finish
-> have to Vnt
21. C - eating
-> feel like Ving
22. B - creep
-> notice sb Vnt
23. D - to give
-> forget to Vnt: quên làm gì