1 When I got to the check-in desk I suddenly realized that I forgot my passport.

2 When we arrived back from our holiday we found that our dog is missing.

3 When the film started I realized immediately that I’ve watched it before.

4 I couldn't answer any of the exam questions because I haven’t studied.

5 We spent 20 minutes in the car park looking for the car because we couldn't remember were we parked it.