1. i was lucky. i found the solution (in/by/on) accident.
2. we can't go by train. the train-drivers are (in/by/on) strike.
3. they've promised me more money, but i haven't got it (in/by/
on) writing
4. i was (under / by / out of the impression that you enjoyed work-
ing here.
5. you can contact me (at/on/by) the phone or (at/on/by) e-mail.
6. sometimes in a shop they ask you: “how do you want to pay? "
you can answer: "(in / on/by) cash. (in / on/by) cheque. (in /
on/by) credit card."
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