阅读短文，从方框中选择恰当的词语并用其适当形式填空，使短文完整、通顺。每个限用一次。
| choose，think of, quiet，bring，like，idea， it，make，instead，plant |
Linda and Laura were very excited because it would be their mother's birthday next Monday. Their mother loved
____and she knew a lot about them. On Thursday, the two girls pretended (假装) that they were going out to buy eggs and bread with their father.
____they went to the plant store where their mother often went. With their father's help, they
____a plant with beautiful flowers. They were sure their mother would like
____.
When they got home，their mother was busy in the kitchen, so they
____ carried the plant to their room. They wondered where they could put it because they wanted to give their mother a surprise on Monday. They looked around the room carefully. Finally, the two young girls had a(n)
____. They put the plant in a big box and
____it to the top of the bookcase. After it was done, they were very happy.
However, no one
____watering the plant over the next few days. They just treated (对待) the plant
____any other gift. When their mother's birthday came, they opened the box and found a dead(枯萎的) plant with dry flowers, but it still
____their mother happy.
机械能守恒的是：
