导游讲解的节奏可体现在讲解的音量、速度、声调和停顿等方面。
参考答案：对
甲乙两地相距140千米，一辆汽车每小时行x千米，行了2小时，还剩下100千米没有行．
— Are you worried when your son often plays computer games?
— Yes. I think playing computer games _____ on teenagers. [ ]
A. have a good effect
B. has a good effect
C. has a bad effect
D. have a bad effect
