史料记载：“周武王所封弟子同姓者甚众，然后属疏远，相攻击如仇敌，诸侯更相诛伐，周天子弗能禁止。”据此我们可以推断西周后期被破坏的主要是(     )

铜仁市对城区主干道进行绿化，计划把某一段公路的一侧全部栽上桂花树，要求路的两端各栽一棵，并且每两棵树的间隔相等。如果每隔5米栽1棵，则树苗缺21棵；如果每隔6米栽1棵，则树苗正好用完。设原有树苗x棵，则根据题意列出方程正确的是（　　）

物理变化与化学变化最本质的区别是有没有____ 生成．

    What kind of music do you like? How do you ____when you listen to your favorite music? Do you think music can make people feel better or help ____learn?

    Jen Morgan is a music therapist ( 治疗专家). She works with children with disabilities (缺陷). Jen ____music to help them learn new things. She can also help them with their ____and memory (记忆力).

    There are different ____ for doing music therapy. Jen gets the children to listen to music and sing or play along. The children also enjoy moving to the music. Jen asks them to try to ____songs they like, too.

    Jen writes songs and uses them in her therapy work. "I've probably written more than 200 songs," she says. "I write songs about ____ about getting dressed, about flowers, about my favorite food – you name it Sometimes the children help me write songs."

    Jen loves her job ____a music therapist "I'm very lucky to have this job," she says. It's ____to see how music can help children with disabilities Often children are ____ when I first meet them. But they soon start having fun and enjoying the music. Music makes people feel good!

1917年,《新青年》第2卷第6期发表了胡适的《朋友》:“两个黄蝴蝶,双双飞上天。不知为什么,一个忽飞还,剩下那一个,孤单怪可怜。也无心上天,天上太孤单。”该诗(    )。