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问题 选择题

下图为某商品甲的价格走势图（横轴为时间，纵轴为价格，单位为“元／公斤”）。下列说法正确的有[ ]

①从A点到B点，甲商品的替代品的需求量会增加

②从A点到B点，甲商品的供给量会减少

③从B点到D点，甲商品的互补商品的需求量会持续下降

④从B点到C点，甲商品的购买者可能会持币待购

A、①③

B、②④

C、③④

D、①④

答案

答案：D

选择题

已知反应：①101kPa时，2C(s)＋O2(g)＝2CO（g）；△H＝－221 kJ/mol

②稀溶液中，H＋(aq)＋OH－(aq)＝H2O(1)；△H＝－57.3 kJ/mol

③红磷的化学式为P，白磷的化学式为P4，已知

P4(s)+5O2(g)="P4O10(s)" △H＝－3093.2 kJ/mol

4P (s)+5O2(g)="P4O10(s)" △H＝－2954.0 kJ/mol

下列结论正确的是（     ）

A．由于红磷转化为白磷是放热反应，等质量的红磷能量比白磷低

B．稀硫酸与稀NaOH溶液反应的中和热△H＝57.3 kJ/mol

C．碳的燃烧热大于-110.5 kJ/mol

D．稀醋酸与稀NaOH溶液反应生成1 mol水，△H 大于 －57.3 kJ/mol
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单项选择题

Prior to the UML, there was no clearleading (66) Ianguage. Users had to choose from among many similar modeling languages with minor differences in overall (67) power. Most of the modeling languages shared a set of commonly accepted concepts that are expressed slightly differently in various languages. This lack of (68) discouraged new users from entering the OO market and from doing OO modeling, without greatly expanding the power of modeling. Users longed for the industry to adopt one, or a very few, broadly supported modeling languages suitable for (69) usage.

Some Vendors were discouraged from entering the OO modeling area because of the need to support many similar, but slightly different, modeling languages. In particular, the supply of add-on tools has been depressed because small vendors cannot afford to support many different formats from many differem (70) modeling tools. It is important to the entire OO industry to encourage broadly based tools and vendors, as well as niche products that cater to the needs of specialized groups.

（70）处填（）。

A．internal

B．external

C．front-end

D．back-end
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