Try reading the following sentences as fast as you can. “She sells seashells by the seashore. The shells she sells are surely seashells. So if she sells shells on the seashore, I’m sure she sells seashore shells.”
Not very easy, was it? What you’ve just read is called a tongue twister (绕口令). It is an exercise made up of sounds that are hard to pronounce(发音，读) in order to help people pronounce words faster and more correctly. Try the next example.
“Peter Piper picked a peck of pickled pepper. Did Peter Piper pick a peck of pickled peppers? If Pete Piper picked a peck of pickled peppers, where’s the peck of pickled peppers Peter Piper picked?”
Tongue twisters usually do not have much meaning. They are just designed to improve people’s ability to pronounce words. Although they may be very difficult, these exercises are very important to people who are trying to speak English correctly. This is because tongue twisters help people to tell the differences between similar sounds.
So if you wish to pronounce words more smoothly, you’d better try picking out some tongue twisters and practicing them.
小题1:Tongue twisters are helpful in improving ___________ skills.
A．listening
B．writing
C．pronunciation
D．communication小题2:The first tongue twister is hard because ___________.
A．it is very boring to read
B．it teaches us a lot of knowledge
C．we don’t know who “she” is
D．the sounds of “s” and “sh” are similar小题3:The passage is probably taken from _________ in a school newspaper.
A．Story Time
B．Study Garden
C．Latest News
D．Lost and Found
时，沿斜面方向上的合力为零，故可能，B正确，当方向竖直向下时，受到的安培力方向水平向左，当
时，合力为零，故C正确，当磁场方向水平时，受到的安培力方向，受到的安培力竖直向上，所以当安培力等于重力时，合力为零，即
，D正确，