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问题 单项选择题

某垃圾填埋场渗沥水污染了地下水，而地下水的自净作用缓慢。其主要原因是

A．有机物含量高

B．有大量难分解的有机物

C．没有阳光无法进行光解反应

D．流动缓慢溶解氧少

E．温度较低

答案

参考答案：D

单项选择题

A multicast router may receive thousands of multicast（）every day for different groups. If a router has no knowledge about the membership status of the（）, it must broadcast all of these packets. This creates a lot of traffic and consumes（）. A better solution is to keep a list of groups in the network for which there is at least one loyal member.（）helps the multicast router create and update this list. For each group, there is one router that has the duty of distributing the（）packets destined for that group. This means that if there are three multicast routers connected to a network, their lists of groupids are mutually exclusive. A host or multicast router can have membership in a group.

A multicast router may receive thousands of multicast（）every day for different groups.

A．packets

B．errors

C．reports

D．alarms
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单项选择题 A3/A4型题

患者王某，男，16岁，学生，因"面部、上胸背部丘疹、脓疱、结节、囊肿5个月"入院。患者5个月前无明显诱因在面部、上胸背部出现丘疹、脓疱、结节及囊肿，有触痛，时轻时重，逐渐增多，部分皮疹有破溃、结痂，形成散在瘢痕。发病以来一般情况可，睡眠、饮食及大小便无特殊。既往无药物过敏史，无服用糖皮质激素、溴、碘等药物史，也无焦油、沥青、卤代烃类化合物接触史，否认家族中有类似患者。

按照Pillsbury分类法，该患者痤疮最可能属于几度损害（）

A.Ⅰ度（轻度）损害

B.Ⅱ度（中等度）损害

C.Ⅲ度（重度）损害

D.Ⅳ度（严重度）损害

E.不确定损害程度

F.无法分类
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