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问题 单项选择题

以下哪种条件满足占用丢失报警使用条件（）

A.自动站间闭塞区间、虚拟自动闭塞区间、站内非集中区

B.自动闭塞区间

C.联锁设备停用

D.非列车占用轨道红光带

答案

参考答案：B

计算题

黄铜是铜和锌的合金。向一定质量的黄铜样品中加入196g稀硫酸，恰好完全反应，产生0.2g氢气。

（1）（3分）求所用稀硫酸的溶质质量分数

（2）（3分）除了可求出稀硫酸的溶质质量分数外，你还能求出的化学量有           。（填序号，错选不得分）

①锌的质量        ②铜的质量分数   ③锌的质量分数    ④硫酸锌的质量    ⑤硫酸溶液的体积   ⑥反应后溶液溶质质量分数

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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.

（67）处填（）。

A．control

B．expressive

C．conductive

D．interactive
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