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I/
1. B ( the length of the journey)
2. B ( children under sixteen pay half, and those under five travel free.)
3. D ( you usually buy bus tickets from the conductor.)
4. A from ( On the underground railway....ticket office)
II/
5. A by
6. B bởi vì
7. C many
8. B quickly
B/
I/
9. B Tuy nhiên
10. B đã từng
11. D take
12. C mặc dù
13. B ours
14. A or
15. B find sth adj
16. B bị động thì tlđ
17. A used to V : đã từng làm gì