10. The friends wanted to run from the mouth of the Thames to its start.
11. There was a natural mark which indicated the start of the river Thames.
12. During the marathon the weather was fine.
13. After the accident with Martin’s leg, Tom carried his rucksack.
3) Not stated
14. The friends spent all their nights in the tent.
15. The friends learnt lots of historical facts from the lock-keepers.
16. Near London the Thames was closed to navigation.
17. Their marathon route went through the centre of London.