阅读短文，从每小题所给的 A 、B 、C 、D 四个选项中，选出可以填入空白处的 最佳选项。
Mr. Worth liked spending time with his grandson, Shawn. He enjoyed teaching him some of the things that couldn't be 1 at school. Grandfathers always have a close relationship with their grandchildren.They pass down wisdom(智慧) that will be 2 to the younger generations .
One day, while Mr. Worth was reading a book, Shawn ran into the house. He told his grandfather about a science3 that he was excited about.
Each student was going to4 a pot of bean plants. When the plants became big, the students were to plant them in a garden. The student who grew the5 bean plant would be praised.
Shawn showed his grandfather the bean seeds (种子). He explained that his6 taught them how to make the seeds grow in class. First, put the seeds on a wet paper towel. Then, put them near a7 to let in some sunshine. When the seeds sprout (发芽) ，they are ready to be moved into a small pot.
When Shawn finished, Mr. Worth said, " You do just as you've learned,8 I want to show you one more thing about growing plants."
"When I was a boy, my father showed me9 to grow strong plants, " he continued. " When the plant is starting out, you can put some10 on it." Shawn looked at his grandfather in surprise and could11 believe what he said.
"Doesn't the weight stop the bean from growing?" he asked.
"No, of course not. This way, you will force(迫使) the bean plant to be stronger. If you give it 12 it wants, it will grow too fast and it will be13 . Then, when the first big wind blows, it will 14 ."
Shawn listened to his grandfather carefully. He wanted to grow the beans in the way his grandfather 15 .He could hardly wait to tell his friends what he had learned.
B. 
C. 
D. 
E. 
F. 
