问题 选择题

以下操作可以达到实验目的是(  )

A.用灼烧的方法除去铜粉中混有的少量木炭粉

B.加入过量Fe2O3反应后过滤,除去Fe2(SO43溶液中少量的硫酸

C.加水溶解并过滤除去CaO中的CaCO3

D.通入适量的氧气后点燃除去二氧化碳中少量一氧化碳气体

答案

答案:B

完形填空

US president Barack Obama is probably 小题1:______ most powerful person in the world. But what was his high school life 小题2:_______? You can find answers to the question in his “Back to School” speech 小题3:______ (give) on September 13, 2010.

“I know some of you may be nervous about starting a new school year and worried about 小题4:_______ that’ll be like. Here is what I tell you: nobody 小题5:_____ (get) to write your destiny (命运) but you. Your future is in your hands. Your life is what you make of it. And nothing is beyond your reach. So long as you’re willing to dream big. So long as you’re willing to work hard. So long as you’re willing to stay 小题6:_____ (focus) on your education. An education has never been more important. I’m sure there will be times 小题7:_____ you’re staying up late for a test, or dragging (费力地拉起) yourselves out of bed on a rainy morning, and wondering 小题8:_____ it’s all worth it. Let me tell you: Nothing is as 小题9:_____ in life as your education. In other 小题10:______ (word), the farther you go in school, the farther you’ll go in life.

An unforgettable experience I recently had made me 小题11:______ (see) how important friendships are and the need to have a better understanding of friends. A friend is a person 小题12:______ is always there to encourage and support you whenever you’re in trouble. A friend is a person who’ll try to do what he or she can小题13:______ you. A friend is a person who’s overjoyed seeing you win and who will share your sorrow when you’re 小题14:________ (disappoint).

For my part, friendship is like a 小题15:______(price) gift: It can’t be bought for any amount. It’s also a shining light of hope. If you have friendship, you’ll never feel小题16:_______(alone).

Exactly 10 years ago, 189 heads of state 小题17:______ (gather) in New York. They set a number of goals. These goals included helping poor people, educating children and protecting the environment. The leaders agreed to do their best to meet the goals 小题18:_______ 2015.

With only five years 小题19:_______ (go), about 140 world leaders got together in New York on September 20. Their小题20:________ (三天的)meeting was to talk about their work on the goals.

问答题