根据上下文意思，用所给单词的恰当形式完成下列短文。

      Have you ever tried to dub (为……配音) an English film? It____ (be) very interesting! I____ (join) in a film dubbing competition at our school last week. It was difficult for me because my spoken English is not so good. But I still decided to have a try. First, I chose my favourite part of a movie. I tried my best to follow the characters’ pronunciation. When I showed my work to my____(classmate) in this competition, to my surprise, they were proud of me! I love such interesting competitions. They not only build my self-confidence (自信) but also improve my spoken English.

         Now, everyone____(practice) English like me. We hope we____ (have) chances to join more and more competitions in the future.

小明背对小亮，让小亮按下列四个步骤操作：

第一步分发左、中、右三堆牌，每堆牌不少于两张，且各堆牌的张数相同；

第二步从左边一堆拿出两张，放入中间一堆；

第三步从右边一堆拿出一张，放入中间一堆；

第四步左边一堆有几张牌，就从中间一堆拿几张牌放入左边一堆．

这时，小明准确说出了中间一堆牌现有的张数．你认为中间一堆牌的张数是____．

下列关于人体运动系统的叙述，正确的是（    ）