《2025年情景导学高中英语选择性必修第二册外研版》

Challenges of living in space
Living in space has its challenges. Microgravity (微重力) means that astronauts have many obstacles to their regular routines, such as eating and sleeping.
While some food items, such as cakes and fruit, can be eaten in more or less the same way that they are eaten on Earth, water needs to be added to much of the food that is eaten in space. Nevertheless, a menu for an astronaut can still be varied and balanced. And as salt and pepper would simply float away, astronauts are provided with these in liquid form.
There is no up or down in space. Astronauts are weightless and can sleep in any orientation (定向). However, they have to attach themselves so that they don't float around and bump into something. They usually sleep in sleeping bags located in small crew cabins. Each crew cabin is just big enough for one person.
Astronauts have to exercise for more than two hours a day to prevent the loss of muscle and bone mass caused by living in microgravity. Because astronauts do not have to use their lower body muscles to walk or stand in space, their lower backs and leg muscles begin to lose strength unless they exercise regularly.
Morning routines also get shaken up (调整) by microgravity. In the absence of regular showers and sinks, astronauts use special soap and shampoo which do not need to be rinsed off with water and they spit their toothpaste into towels. They also have to use special toilets which have leg restraints (安全装置) and a vacuum for waste.
阅读完以上段落,让我们一起来讨论以下问题吧！
1. Why do astronauts have to exercise in space?
2. Which part of the life in space would be the most challenging for you? Why?

答案： 1. To prevent the loss of muscle and bone mass caused by living in microgravity.
2. （示例）Morning routines. Because there are no regular showers and sinks, and they have to use special soap, shampoo and toilets, which is very different from life on Earth. (答案不唯一，合理即可)