Не уверенна, но:
1. was walking, passed.
2. was looking, saw.
3. were answering, entered.
4. were drinking, came.
5. was walking, went.
6. was reading, came sat.
you must switch off your phone when you drive
you mustn't cross the road... (... будет означать что оставшаяся часть одинакова с оригинальной)
you must be careful when you...
you must walk...
you mustn't cycle...
you must fasten...
you mustn't drive...
you must cycle in...
Некоторые проблески американской истории
Знаменитый или известный )