低温高浓度有利于碳酸钠和硫酸钠结晶析出。

单词拼写 根据所给汉语或英语首字母写出短文中所缺英语单词的正确形式。（共10个小题，每小题0.5分）

Last week, my friends and I talked about the rules in our school. Here are some of our ideas.

At our school, we have to wear uniforms every 小题1:d______. The problem is that all my classmates think the uniforms are 小题2:丑的______.We think young people should 小题3:l______ smart and so we would like to wear our own clothes. Our teachers believe that if we did that, we would concentrate more on our clothes than our studies. We don’t小题4:同意________.We would feel more comfortable and that is 小题5:g______ for studying. If we can’t do that, we should be小题6:允许__________to design our own uniforms. That would be a good way to keep both teachers and 小题7:学生___________ happy.

Besides, vacations should be longer. At present they’re too小题8:s______. Longer vacations would give us time to do things like volunteering. Last summer I had a(n) 小题9:机会_________ to volunteer at the local hospital,小题10:b________ I couldn’t because I had to go back to school.

2011年，某铜加工企业需要在11月份进口一批铜作生产原料。为了防止未来铜价上涨，该企业决定采用期货和期权进行套期保值。该企业在9月初以3650美元／吨的价格买入LME的11月份铜期货，同时买入11月份的铜的看跌期权，执行价格为3680美元／吨，支付权利金60美元／吨。

如果铜现货价格跌到3295美元／吨，至11月初，铜期货价格下跌到3300美元／吨，该企业可以选择行使期权，将原有的多头头寸对冲平仓，同时企业可以在现货市场低价购买铜原料，则实际采购成本为（）美元／吨。

A.3295

B.3325

C.3275

D.3255

经过电镀处理的贱金属眼镜架

在西北地区已勘探出石油储量丰富，正在开发中的大油田位于 [ ]

A．吐鲁番盆地

B．柴达木盆地

C．四川盆地

D．塔里木盆地

咨询建议初步形成后，咨询团队与客户进行研讨方案，方案的研讨内容主要是( )。

A．创新性与科学性

B．有效性与可行性

C．科学性与有效性

D．创新性与可行性