地震发生时，下列避险措施正确的是(    )

  ①迅速跑到开阔地带  ②乘汽车逃命  ③立即躲到坚固的桌子或床下面，就地避震  ④应站着不动

已知X元素的原子的K、L层的电子数之和比L、M层的电子数之和多1个电子．Y元素的原子最外层电子数比内层电子数少3个．Z元素核外有3个电子层，最外层有3个电子．W元素最高化合价是最低化合价绝对值的3倍，它在最高价氧化物中的质量分数为40%．

    In China, there are many traditional(传统的)holidays. The most important one is the Spring Festival. People like it very much. On the Spring Festival, people don't work. Children don't go to school. People clean their rooms. Mothers make dumplings. Kids can get lucky money. Besides this festival, the Dragon Boat Festival and the Mid­Autumn Festival are also popular. On the Dragon Boat Festival, people eat zongzi and have dragon boat races. On the Mid­Autumn Festival, people eat moon cakes and watch the moon. How happy they are!

酬乐天扬州初逢席上见赠

（唐）刘禹锡

巴山楚水凄凉地，二十三年弃置身。

怀旧空吟闻笛赋，到乡翻似烂柯人。

沉舟侧畔千帆过，病树前头万木春。

今日听君歌一曲，暂凭杯酒长精神。