Complex sentence: A giant alien warrior rampages through a supermarket pushing things over and squeezing bottles, the Doctor and Martha land inside the supermarket to pick up some milk, the Doctor is picked up and threatened by the warrior.
Split into simpler sentences: A giant alien warrior rampages through a supermarket pushing things over and squeezing bottles as the Doctor and Martha land inside the supermarket to pick up some milk. The Doctor is picked up and threatened by the warrior.