If Ross hadn't been late, he wouldn't have missed the train.
If he hadn't missed the train, he would have sat on the bench.
If he hadn't sat on the bench, he would have found the cheque of £100,000.
If he hadn't found the cheque, he would have taken it to the bank.
If he hadn't taken the cheque to the bank, he wouldn't have received £10,000 reward.
Ответ: See above