阅读下面短文，掌握大意，然后从A、B、C、D四个选项中选出最佳选项。
Think before we speak!
It was a sunny and enjoyable day. Everyone in the 1 station was waiting for the train to arrive. Among the crowd, there was a group of young friends who were on board for vacation.
It was a 2 station with a lot of people and some juice shops, coffee and tea stalls, newspaper shops, etc. The train was arriving and everyone prepared to 3 the train to their seats.
The group of friends made loud noise to 4 the train as it moved into the station. They ran to get their seats 5 anyone entered the train.
The empty seats were 6 and the train whistled to move. An old man with a young boy aged around 15 had their seats just next to the friends' group. The young boy was so 7 to see everything. He cheered, "Dad, the train is moving and the things are moving backward."
His father8and nodded his head.
As the train started moving fast, the young boy again screamed, "Dad, the 9 are green in color and run backward very fast." His father said, "Yes, dear," and smiled
Just like a kid, he was watching everything with great 10 .
A fruit seller passed selling apples, bananas and oranges. The young boy asked his dad, "I want to eat 11 ." His father bought some for him. He said, "Oh, this apple looks a lot sweeter than it tastes. I love this color. " The group was watching all the12 of this boy and asked the boy's father, "Is your son having any problem? Why is he behaving so 13?"
"His son is mad, I think," a friend from the group made fun of him and shouted.
The father of the young boy, with patience, 14 the friends' group, "My son was born 15 . Only a few days ago he was operated. He is seeing different things in his life for the first time."
The young friends became very quiet.
