X、Y、Z均为短周期主族元素，它们原子的最外层电子数之和为10。X与Z同族，Y最外层电子数等于X次外层电子数，且Y原子半径大于Z。下列叙述正确的是(
---Look! So many colorful bicycles in two lines over there. ---They’re for public. This ______ of green smart traffic is everywhere in Xiangyang city. A. number B. pair C. kind D. piece
下列地区中太阳能最丰富的是 A. 东北平原 B．四川盆地 C．青藏高原 D．海南岛
There _____ a sports meeting in our school next week. A. will have B. is gong to have C. are going to be D. is going to be
《水调歌头·明月几时有》中表达了与亲人共赏人间美景的美好愿望的诗句是 ， 。
下列四大地理区域差异对人类活动的影响正确的是（ ） A、北方多旱地，民居多为平顶屋 B、南方地区河流众多，内河航运普遍 C、
设椎实螺的螺壳向右旋是由显性基因D控制，螺壳向左旋是隐性基因d控制。若以两种椎实螺进行杂交（雌dd X 雄DD），则以下有关 F1和F2表现型的叙述正确
The traditional view is _______ we sleep because our brain is “programmed” to make us do so. A. when B. why
