问题 3选择型Why does ice float on water?Ice is heavier than waterIce is denser than waterIce is less dense than water
问题 11选择型What was the main challenge Joe and Simon faced while descending the mountain?AvalancheSnow stormWild animals
问题 12选择型What unfortunate event happened to Joe while descending the ice cliffs?He got lostHe broke his legHe ran out of supplies