题干

玉兰、海棠等植物在早春时节,当叶片还没有完全长出时,却可以开出满树娇艳的花朵.推测这些花瓣中有机物的主要,正确的是(  )

A:是根从土壤中吸收并运输到花瓣的

B:是花瓣在光照条件下合成的

C:是树皮将二氧化碳和水转变成的

D:是叶在上一年制造并储存于树干的

上一题 下一题 0.0难度 选择题 更新时间:2019-01-17 08:44:47

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D

同类题1

阅读理解

    As an exchange student,I must admit (承认) that at first America was a big culture shock for me.

    I stayed with a host family in a small town.My host parents organized a lot of activities in my spare time so that I wouldn't miss home or feel lonely.

    However,life was hard to get used to.My main problem was with the language.I failed to understand much in the first few weeks because everyone spoke so fast.ThoughI managed to get used to it.I still have problems because they used a lot of idioms (习语).

    Another difference was with the food.My host family always had bread,potatoes and salad for meals.I really miss the dumplings,rice and delicious dishes from home.

    School was a big shock too.They do not require students to wear uniforms,so students can wear almost whatever they like.Some students have strange hairstyles (发型) as well.Some students even have pink or purple hair!

—By Brad Li

    My dream was to see some real snow,so during the Christmas holiday,we took our passport (护照) and flew over the Pacific to Calgary,Canada.We took a bus to a ski resort in the Canadian Rockies.As the bus climbed through the mountains,we saw the thick snow on the trees.I was dying to get out and play with it.At last,we reached the resort and quickly jumped out of the bus.This was our first experience with snow.We were like little children—we made snow balls,and threw them at one another.Then we check in at the hotel.

    The next day,we put on our ski suits and gloves,took our skis and went outside onto the snow.Our instructor took us to a gentle slope (斜坡),and showed us some basic skills.To be honest,the first lesson was not a great success.I kept on falling over,and I had to hold on to a rope to keep my balance (平衡).

    However,the next day,I only fell over a few times,and I managed to do a few rapid runs.I felt pleased with myself,and my instructor told me I was doing much better.Although it was very cold,I spent most of my holiday skiing.I had a wonderful time.

—By Vanessa

同类题2

人民币加入SDR,激起了人们对货币国际化的思考和讨论,其实货币国际化作为一个过程,具有丰富的内涵和广泛的影响。结合所学知识,阅读下列材料,回答问题。

材料一   19世纪,英国为代表的国家相继采用了金本位制度,人们在国际贸易等国际经济活动中不仅可以直接用黄金进行交易,也可以用大家普遍认可的货币来进行交易。由于当时英国是世界上经济最强大的国家,基于对英国经济的信任以及对英镑兑换黄金的信任,各国都愿意持有英镑并用英镑进行国际结算。显然,如果各国持有黄金并用于国际结算,不仅要支付黄金的保管费用,而且还要支付较高的结算成本,但是,如果各国在伦敦开设英镑账户并通过伦敦银行进行国际结算,不仅可以得到利息收益,而且只需要支付较低的结算成本。在这样的情况下,英国的主权货币英镑便成为了国际货币。

——张子宇《英镑、日元和欧元的国际化历程》

材料二   布雷顿森林体系崩溃,牙买加体系建立,各国货币不再规定含金量,黄金也不再用于官方结算,黄金的货币使命终结。……而当前美元仍然占各国外汇储备的65%左右,国际外汇交易的40%以上,国际贸易结算的50%以上……现行国际货币体系是一种浮动汇率体系。……弹性化、多样化的汇率制度符合国际经济一体化、资本流动量剧增,各国发展特色化的客观要求,外围国家尤其是发展中国家在经济开发、资本项目自由兑换化的过程中,汇率制度的弹性化为其保持货币政策的相对独立性提供基础前提。

——朱丰根、朱延福《现行国际货币体系基本特征与问题分析》