单项选择题 学校音乐课外活动要坚持面向（    ）学生，使每一个学生的音乐潜能得到开发并从中受益。 A、全体； B、音乐特长； C、音乐后进； D、音乐爱好

不定项选择 A system is called linear if the principle of superposition applies.

多项选择题 What are the disadvantages of package tours?A. The schedules are usually very tight.B. There’s a chance that you may not be able to do or see everything.C. You may get stuck with annoying people.D. The price are usually too expensive.