五、单项选择 (15分)() 21. I think _ is meaningful for us to help other people.A. it B. that C. this D. its()22. - Who joined Oxfam Trailwalker last year, Sam? - Mile _.A. joined B. would C. did D. was() 23. People over 18 can group _ into a team of four people and join the charity walk.A. they B. their C. theirs D. them() 24. They should plan _ during the walk.A. what are they going to carryB. what they are going to carryC. how are they going to carryD. how should they carry
