1. swim ( 现在分词 )—— swimming
2. come( 现在分词 )—— coming
3. dance (-ing形式)—— dancing
4. ski (-ing形式) ——skiing
5. sit (-ing形式)—— sitting
6. fly (-ing形式) —— flying
7. stay (-ing形式) —— staying
8. travel (-ing形式) ——travelling
9. cry (-ing形式) ——crying
10. play (-ing形式) —— playing
11. listen (-ing形式) —— listening
12. collect (-ing形式) —— collecting
13. make (-ing形式) —— making
14. take (-ing形式) —— taking
15. write (-ing形式)—— writing
16. read(-ing形式) ——reading
17. clean (-ing形式) —— cleaning
18. sing (-ing形式)—— singing
19. sweep (-ing形式) —— sweeping
20. run (-ing形式) ——running