[填空题]MTF Ltd.
Heating Systems Manufacturer
Date company started (16) ______
Company’s market position due to (17) ______
Plans to invest in (18) ______
Rewards employees with (19) ______
Training programme has received (20) ______ (from local government)
Promotes staff with good (21) ______
Business section needing improvement: (22) ______

[填空题]MTF Ltd.
Heating Systems Manufacturer
Date company started (16) ______
Company’s market position due to (17) ______
Plans to invest in (18) ______
Rewards employees with (19) ______
Training programme has received (20) ______ (from local government)
Promotes staff with good (21) ______
Business section needing improvement: (22) ______

[单项选择] Home Heating
Central heating became popular only after the Civil War. Typically, coal-burning furnaces (火炉) fueled the early systems. Natural gas had developed into the leading fuel by 1960. Its acceptance resulted in part from its wide uses. Because it comes primarily from U.S. and Canadian fields, natural gas is also less vulnerable (脆弱的) than oil is to war. Oil remains the most important fuel in a few areas, such as New England.
Electric heating dominates most areas with mild winters and cheap electricity, including the South and the Northwest. It was made popular at least in the South by the Iow cost of adding electric heating to new houses built with air-conditioning. Bottled gas, which is somewhat more expensive than utility gas, is the fuel of choice in rural areas not served by utility pipelines. Wood is the leading heating fuel in just a few rural counties.
Home heating, which accounts for less than 7 percent of all energy consum
A. 1978.
B. 1960.
C. 1997.
D. 2000.

[单项选择]关于焦点的MTF叙述正确的是（）
A. 最大值为0
B. 大小与焦点大小无关
C. 越大越好
D. 是表示对比度的参数
E. 为1时表示影像消失

[单项选择]下列关于MTF的组合，错误的是（）
A. MTF--影像清晰度的评价
B. 屏-片体系MTF--使用矩形波测试卡
C. MTF上升--空间频率高
D. 焦点MTF测定--傅氏变换法
E. MTF上升--屏-片感度低

[单项选择]列关于MTF的组合，错误的是 （）
A. MTF--影像清晰度的评价
B. 屏-片体系MTF--使用矩形波测试卡
C. MTF上升--空间频率高
D. 焦点MTF测定--傅氏变换法
E. MTF上升--屏-片感度低

[单项选择]Supersize SurpriseHow does indoor heating affect our life
[A] It makes us stay indoors more.
[B] It accelerates our metabolic rate.
[C] It makes us feel more energetic.
[D] It contributes to our weight gain.

[单项选择]关于调制传递函数（MTF）的描述，错误的是（）
A. 屏-片体系MTF使用正弦波模板
B. MTF向上，屏-片感度向下
C. MTF测定使用微密度计
D. MTF向上，空间频率向下
E. MTF影像清晰度评价

[单项选择]X线管焦点的调制传递函数(MTF)的叙述，错误的是
A. 是描述焦点产生的模糊使影像质量受损的函数
B. MTF的最大值为0，最小值为1
C. H(w)＝1表示影像的对比度与射线对比度一致
D. H(w)＝0表示影像的对比度＝0，影像消失
E. 焦点的MTF测试方法为狭缝照相法