语法填空（本题有10小题，每小题1分；共计10分）
阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空。
Try reading the following sentences as fast as you can. “She sells seashells（贝壳） by the seashore（海边）. The shells she sells are surely seashells. So if she  _shells on the seashore, I’m sure she sells seashore shells.”
Not very easy, was it? What you’ve just read is  (call) a tongue twister (绕口令). It is an exercise made up of sounds that are hard to pronounce in order to help people pronounce words faster and  _correctly. Try the next example.
“Peter Piper picked a peck of pickled peppers. Did Peter Piper  _(pick) a peck of pickled peppers? If Peter Piper picked a peck of pickled  _, where’s the peck of pickled peppers Peter Piper picked?”
Tongue twisters usually do not have much  (mean). They are just used to improve people’s ability to pronounce words. Although they may be very  , these exercises are very important to people who are trying to speak English  _(correct). This is because tongue twisters help people to tell the differences between similar sounds.
So if you wish   words more smoothly（流畅地）, you’d better try picking out some tongue twisters and  _(practise) them.