3.
阅读短文,判断以下问题。
There are
many kinds of trees. All trees have roots. The roots hold trees in the ground.
The roots soak up ( 吸收
) water and food. Then trees get water and food from the roots. You can't see
inside a tree. But you can study how water moves through trees.
First, get
a stalk ( 茎 ) of celery (
芹菜 ) and cut off its end. Put red colour in a cup of
water. Then put the stalk of the celery into the red water. Then we can see the
red water moving up in the celery easily.
After half
an hour, take the celery out. Cut it in half. Your celery should be red. This
is because the water moved up the stalk. Water moves through trees in the same
way as it moved through the celery.