珠江三角洲城镇化发展过程中可能出现的问题有( )①劳动力资源不足② “三废”污染加重③饥饿贫困④大片良田被占用
A:①②
B:②③
C:③④
D:②④
2008年北京奥运会的“祥云”火炬燃烧时的主要反应为:5O2+X 3CO2+4H2O。由此可知,火炬燃料X的化学式为:()
“之”字用法与众不同的一项是( )
Voyages
By Neil Waldman
Travel with young Abe Lincoln down the Mississippi River, taking his boat down to New Orleans. Along the way, Lincoln finds himself on his own voyage of discovery. It is an amazing experience with risk and excitement.(Chapter book)
Through Georgia's Eyes
By Rachel Rodriquez and Julie Paschkis
Discover the wideness and wonder of deserts and rivers through the eyes of painter Georgia O'Keefe. Deep-colored paper paintings show the artist's imagination and the amazing sightseeing that inspired her work. (Picture book)
A Horn For Louis
By Eric A. Kimmel and James Bernardin
Louis Armstrong was too poor to have a real music instrument, but he had a horn(喇叭). Jazz and blues music was everywhere in the streets of New Orleans. This is the story of how Louis got his first real "horn", when he was just a boy with a dream of becoming a musician. (Chapter book)
Go, Go America
By Alan Barnard
50 states of fun, with interesting facts — in what state the entertainment capital of the world is, where the first hamburgers were served, what the Cereal Festival is, who hosts the Hog Calling Contest and more.(Picture book)
①今天下雨或不下雨;
②天河电影城某天的上座率达到60%;
③从1,3,5三个数字中任选2个数相加,其和为偶数;
④从一副不包括大小王的52张扑克牌中任取4张,恰好四种花色各一张;
⑤从一个正方体的八个顶点中任取三个顶点,这三个顶点不共面.
其中必然事件有____,不可能事件有____,随机事件有____.(填序号)