Решение:
Нужно выбрать правильный вариант глагола в каждом предложении.
- Always look through the peephole before you open the door.
- Don't run after the burglar!
- A burglar broke into our house yesterday.
- He is installing an alarm system.
- Keep your mobile phone switched on at night.
Ответ: peephole; after; broke into; installing; switched.