题目内容：

    It was only a dollar. Belscher _________ it on the floor. He could easily have _________ it without thinking twice._________, he brought it to his English teacher, Mattison. She suggested that he tape it to the _________ at the front of the classroom. _________ the dollar was lunch money or bus fare for the _________.

Hunter Joe spotted the dollar on the whiteboard. There was a _________ to it, he thought. He asked Mattison why it was there. With nobody _________ it, she replied, "I don't know." Then Joe stuck a second dollar to the board.

That got it rolling. The _________ of the two dollar bills triggered（触发）something in Mattison's students. More began to __________ dollar bills.

The effort __________. Even with no specific __________, many students wanted to be part of whatever this was, for they __________ that the eventual plan for the dollars would be for "something __________" and that their teacher "wasn't going to do anything stupid with the money."

The amount continued to __________ over several weeks. That left Mattison to __________ the best resolution. She kept thinking about Jack Hains, a wonderful human being. He had died of ALS（肌萎缩）, a __________ disease. Jack' wife, Terry raised money for the ALS Therapy Development Institute, which was established to seek a __________ for the disease. Mattison told this to all her classes. By the end of the term, they'd raised over $1,300. They made the __________.

"A group of kids, who were motivated by the mystery of what was __________, have more power than I realize," Mattison said.

1.A.threw B.took C.noticed D.stepped

2.A.ignored B.pocketed C.lost D.put

3.A.Instead B.Otherwise C.Therefore D.Moreover

4.A.wall B.floor C.table D.whiteboard

5.A.Maybe B.Certainly C.Thus D.Obviously

6.A.student B.teacher C.worker D.owner

7.A.truth B.mystery C.phenomenon D.fact

8.A.finding B.claiming C.taking D.seeking

9.A.view B.look C.scene D.sight

10.A.tape up B.take away C.peel off D.deal with

11.A.snowballed B.doubled C.stopped D.dropped

12.A.wish B.determination C.purpose D.appointment

13.A.decided B.doubted C.figured D.worried

14.A.interesting B.fantastic C.wise D.good

15.A.remain B.grow C.decline D.fall

16.A.decided upon B.worked out C.agreed to D.put forward

17.A.dead B.common C.rare D.ordinary

18.A.treatment B.cure C.heal D.test

19.A.difference B.preparations C.donation D.offering

20.A.uncovering B.exposing C.showing D.unfolding