Место точек нужно ставить эти слова: train, plane , bus or metro . 1. the id faster than the bus , but it is not as fast as the plane 2. the train is more expensive than the but it is nit as expensive as the 3. the is not as cheap as the bus , but it is faster than the 4. the is not as expensive as the plane , but it is more comfortable that the 5. the is the cheapest 6. the is the most comfortable
2) metro; plain
3)train; metro
4) train; bus ( metro)
Но могут быть разные варианты, тут нет однозначного ответа, как мне кажется.