男性，31岁。发现左侧阴囊内软性肿块2年，不痛，平卧不消失。结婚4年，未育，检查精液

下列具有正常生育能力的精子数量指标是（）。

A.精子数（2000万～3000万）/mL

B.精子数（4000万～5000万）/mL

C.精子数（5000万～6000万）/mL

D.精子数（3000万～4000万）/mL

E.精子数>6000万/mL

如图是实验室有关氧气制备、收集、验满、验证性质的操作，其中正确的是   [ ]

A．

B．

C．

D．

右侧腹股沟斜疝儿童患者，最恰当的手术方式为（）。

A.单纯疝囊高位结扎术

B.巴西尼（Bassini）法疝修补术

C.佛格逊（Ferguson）法疝修补术

D.麦克凡（McVay）法疝修补术

E.疝成形术

In January 2010 Ami took over an old warehouse with the intention of opening an art gallery. As the warehouse had to be converted, Ami entered into two contracts, one with Bry to do all the necessary plastering and one with Cis, who was to do all the necessary painting. Both Bry and Cis were to be paid ￡5,000. Both received initial payments of ￡1,000 and agreed to have the work completed on 31 March, as the art gallery had to be ready for its fi rst exhibition on 1 May.At the end of February, Bry told Ami that he would not complete the plastering in time unless she agreed to increase his payment by a further ￡1,000. Ami agreed to pay the increased sum in order to ensure that the job was done on time. She then thought it was only fair that she should increase the amount of money promised to Cis by the same amount.However, on completion of the work on time Ami refused to make either of the additional payments to Bry or Cis, beyond the original contractual price.Required:Advise Bry and Cis whether they have any rights in law to enforce Ami’s promise to pay them an extra ￡1,000. (10 marks)

某化工厂联合生产纯碱、镁、阻燃剂。以白云石（CaCO₃·MgCO₃）为原料冶炼镁：经高温煅烧生成的氧化物在还原炉中经1200℃用硅铁还原生成镁蒸汽（铁化合价不变），镁蒸汽经冷凝为粗镁；同时以海水为原料制碱和制阻燃剂。具体流程如下：

（1）分别写出A、B、C的化学式           、           、           ；沉淀池中反应的化学方程式是                             。

（2）硅铁还原生成镁蒸汽时选择低压和1200℃，试分析选择这种反应条件的原因

                                                          。

（3）精制卤水中的MgCl₂与适量石灰乳反应生成碱式氯化镁[Mg(OH)Cl]沉淀，此时溶液中主要溶质是（写化学式）             。

（4）描述流程中相关操作Ⅰ包括过滤、       、      。

（5）已知：Mg(OH)₂(s)→MgO(s)+H₂O(g)－81.5kJ；Al(OH)₃(s)→0.5Al₂O₃(s)+1.5 H₂O(g)－87.7kJ

①Mg(OH)₂能起阻燃作用，其原因是                                  。

②等质量Mg(OH)₂和Al(OH)₃相比，阻燃效果较好的是                     。

（6）某化工厂利用上图所示流程联合生产纯碱、镁、阻燃剂，试分析该生产的优点

                                                                。