题目内容：

    It was only a dollar. Dylan_______ it on the floor as he sat at the back of his English class.

When the school day _______ ,Dylan wandered back to the classroom. The wrinkled old bill was_______ there. He could easily have pocketed it without thinking twice. _______, he picked it up and brought it to his English teacher, Mattison. She was a little_______that he'd turned the dollar in, knowing a lot of people would have just kept it. She_______ that Dylan tape it to the whiteboard at the front of the classroom.

A day or two later, David_______the dollar on the whiteboard. After class, he asked Mattison_______ it was there. She was still _______ the original owner to claim it, so she replied, "I don't know." Then David taped a second dollar to the________,which got it rolling. The________of the two dollar bills, side by side, triggered(触发)________in Mattison's students. More students taped up single dollar bills.

The________ snowballed. The students, among themselves, ________Mattison had some unspoken goal. Ben taped a $20 bill to the whiteboard, Megan another $20.The amount________ to grow over several weeks, ________ it reached$175.76.

She asked the teens whether they minded if she ________  the dollars in their names. Their answer was to tape ________ money to the whiteboard over the next few days to________the amount to over$300. Mattison, choking back tears as she ________ the moment, said she carefully peeled the cash off the board and made the donation.

1.A.dropped B.noticed C.mentioned D.remembered

2.A.ended B.started C.came D.went

3.A.also B.even C.still D.only

4.A.Finally B.Suddenly C.Therefore D.Instead

5.A.surprised B.excited C.relieved D.curious

6.A.discussed B.reported C. explained  D.suggested

7.A.took B.spent C. spotted  D.changed

8.A.when B.why C.how D.what

9.A.speaking to B.returning to C.waiting for D.looking for

10.A.board B.floor C.classroom D.desk

11.A.thought B.sight C.idea D.request

12.A.anything B.nothing C.something D.everything

13.A.problem B.business C.effort D.reputation

14.A.persuaded B.advised C.managed D.decided

15.A.continued B.stopped C.added D.began

16.A.until B.unless C.if D.after

17.A.raised B.donated C.charged D.collected

18.A.easy B.old C.enough D.exact

19.A.meet B.control C.prepare D.push

20.A.made use of B.paid attention to C.thought much of D.looked back upon