问题
选择题
下列各组物质中,不属于同素异形体的是 ( )
A.白磷和红磷
B.氧气和臭氧
C.金刚石和石墨
D.冰和干冰
答案
答案:D
下列各组物质中,不属于同素异形体的是 ( )
A.白磷和红磷
B.氧气和臭氧
C.金刚石和石墨
D.冰和干冰
答案:D
Last August ,our class________ something very special on our school trip .We ________ to Mount Tai .We ________ our trip at 12:00 at night .Everyone in our class _______ a bag with some food and water .After three _______ ,someone _____ at the map and found out we were’t anywhere near the top. My legs _________ so tired that I wanted ______.My classmates told me _______ going ,so I went on.Twenty ________ later ,the sun started to come up .It was so beautiful that we forgot about the last five hours !
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