阅读下面短文，掌握其大意，然后从36—55各题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑。
I was coaching girls’ track in Iowa and there was a young discus（铁饼）thrower on the team with  36  potential（潜力）. Here goes her story.
At the end of our training   37  the district track meet, this discus thrower, Lucy, asked me if she   38  come to the school on Sunday for a little   39  training. I agreed. The year before, she had placed second at the district meet and   40  missed going to the state meet. She had won every discus event,   41  that district meet! And, her throws in the competitions had   42  been between 106’1” and 110’10”.
Something began to   43  me. Why couldn't Lucy   44  to get the discus to 111 feet? I wondered if it was more a psychological barrier（心理的障碍）  45  a physical one. I decided to try something   46 . I made up my mind to   47  to Lucy.
On Sunday, after her drills, I said, “Why don’t you throw five or six good ones for me to  48 ?” She began to throw again, but   49  were farther than what she had already thrown. But, I didn’t tell Lucy. As I was measuring the   50  one, I pulled out some more tape (量尺) and yelled out to her, “ Come to see this! This one is  51 ! ” It wasn’t. Lucy, thinking that this was a personal best, jumped wildly into the air in  52  .
The next afternoon, at the district meet, Lucy   53  with a personal best throw of 114’10”! Just 24 hours after I had lied to her. However, this time she had   54  thrown the discus four feet further than she had ever thrown it before.
Sometimes we   55  our own barriers in our mind. So learn to take control of your mind.
21．A. little          B. great           C. no              D. limited
22．A. after           B. during          C. since           D. before
23．A. could           B. must           C. should         D. would
24．A. helpful        B. extra          C. real           D. regular
25．A. luckily         B. completely     C. narrowly        D. probably
26．A. except         B. including      C. despite        D. with
27．A sometimes       B. always         C. never          D. seldom
28．A. frighten       B. please         C. shock          D. bother
29．A. seem           B. pretend        C. need           D. ask
30．A. apart from     B. rather than    C. because of      D. according to
31．A. impossible     B. familiar       C. new             D. easy
32．A. lie            B. turn           C. reply          D. call
33．A. look           B. measure        C. match          D. take
34．A. many           B. all            C. some           D. none 
35．A. worst          B. closest        C. first          D. final
36．A. higher         B. farther        C. bigger         D. longer
37．A. excitement     B. anxiety        C. puzzlement     D. anger
38．A. disappeared    B. lost           C. won            D. arrived
39．A. actually        B. hardly         C. nearly          D. only
40．A. break          B. remove         C. take           D. set