Here are the completed sentences:
- They had to pack the right clothes and equipment.
- They took a train to the airport so they went by taxi.
- In the Amazon, they had to travel by canoe because there weren't any roads.
- They knew the area well, so they didn't have to take a guide with them.
- They didn't have to sleep in tents. They slept in a cabin - a small, wooden house.
- They had to lock the door of the cabin at night because the jungle is a scary place!