9．
阅读理解
Have
you ever dream ed of traveling in space? To travel in space, we first have to
work out where our food will come from.
Today's
space travellers don't go to the Moon or Mars. They go to the International
Space Station (ISS). There, the spacemen live for weeks to months.
If
you visited the ISS years ago, nearly every kind of food you ate would have
come from the Earth.
In
2014,scientists sent the ISS a space garden with some vegetable seeds（种子）. With
water and some light, the vegetables in the garden grew. Those were the first
foods being grown on the ISS. But the spacemen couldn't eat them and had to
send them back to the Earth. The next year, after scientists made sure
they were safe, the spacemen grew a second crop. This time the vegetables were
ready for the spacemen to eat.
Gardening
is different in space than it is on Earth. Without gravity, plants don't know
which way is up. But they learn how to grow. They send their leaves in the direction
of light and their roots into the soil.
The
spacemen also have grown vegetables as well as flowers. It's important to know
a plant can flower in space, because flowering is part of how some plants make
fruit.
While
the space garden is small for now, hopefully it could one day help provide
people with food on long﹣time space trips.
