理想低通时的频谱利用率为（），升余弦滚降时的频谱利用率为（）。

根据短文内容回答下面的问题。

As you’re using e-mails, remember that sending and getting letters can sometimes bring about serious trouble.

When Jim left the snow-covered streets of London for a holiday in New York, his wife was on a business trip and was planning to meet him there the next day. When he reached his hotel in New York, he decided to send his wife a quick e-mail. But he couldn’t find the piece of paper on which he had written her e-mail address. He tried his best to remember where he had put it, but failed. Unluckily, he made a mistake and sent it to an old woman. Her husband had died a few years ago. When she saw the e-mail, she gave a terrible shout and fell on the floor. Her family rushed into the room and saw the message on the computer.

“Dearest wife, everything is ready for your arrival tomorrow.

Love, Jim.

P.S. it’s hot here.”

小题1:Where was Jim for his holiday?

小题2:Why couldn’t Jim write his wife’s e-mail address correctly?

小题3:Was it hot in London?

2007年，全国研究与试验发展(R&D)经费总支出为3710.2亿元，增长23.5%，研究与试验发展(R81D)经费投入强度(与国内生产总值之比)为1.49%。按研究与试验发展人员(全时工作量)计算的人均经费支出为21.4万元，比上年增加1.4万元。
分活动类型看，基础研究经费支出为174.5亿元，比上年增长12%；应用研究经费支出为492.9亿元，增长0.8%；试验发展经费支出3042.8亿元，增长29.5%。基础研究、应用研究、试验发展经费支出所占比重分别为4.7%、13.3%和82%。
分执行部门看，各类企业经费支出为2681.9亿元，比上年增长25.6%；政府部门属研究机构经费支出687.9亿元，增长21.3%；高等学校经费支出314.7亿元，增长13.7%。企业、政府部门属研究机构、高等学校经费支出占全国总支出的比重分别为72.3%、18.5%和8.5%。
分产业部门看，八大行业的研究与试验发展(R&D)经费投入强度(与主营业务收入之比)超过1%。专用设备制造业为1.95%，医药制造业为1.82%，通用设备制造业为1.53%，电气机械及器材制造业为1.42%，交通运输设备制造业为1.41%，橡胶制品业为1.28%，通信设备、计算机及其他电子设备制造业为1.15%，仪器仪表及文化、办公用机械制造业为1.03%。
分地区看，研究与试验发展(R&D)经费支出超过100亿元的有北京、江苏、广东、山东、上海、浙江、辽宁、四川、陕西、天津、湖北和河南共12个省(市)，共支出2994.6亿元，占全国经费总支出的80.7%。研究与试验发展(R&D)经费投入强度(与地区生产总值之比)达到或超过全国水平的有北京、上海、天津、陕西、江苏、浙江和辽宁7个省(市)。

2007年，研究与试验发展经费支出超过100亿元，但经费投入强度没有达到或超过全国水平的共有几个省市( )

A．4个

B．5个

C．6个

D．7个

收割机粮食损失的种类主要有哪些？

借款人存货周转率是指用一定时期内的( )除以( )得到的比率。

A．平均存货余额，销货收入

B．销货收入，平均存货余额

C．销货成本，平均存货余额

D．平均存货余额，销货成本

汽轮机在冷态启动和加负荷过程中，蒸汽将热量传给金属部件，使之温度升高。