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问题 单项选择题

某钢结构办公楼，结构布置如图所示。框架梁、柱采用Q345，次梁、中心支撑、加劲板采用Q235，楼面采用150mm厚C30混凝土楼板，钢梁顶采用抗剪栓钉与楼板连接。

次梁与主梁连接采用10.9级M16的高强度螺栓摩擦型连接，连接处钢材接触表面的处理方法为喷砂后涂无机富锌漆，其连接形式如图所示，考虑了连接偏心的不利影响后，取次梁端部剪力设计值V=110.2kN，连接所需的高强度螺栓数量（个）与下列何项数值最为接近（）

A．2

B．3

C．4

D．5

答案

参考答案：C

解析：

根据《钢结构设计规范》7.2.2条规定：

10.9级、M16螺栓，预拉力P=100kN；Q235钢材、表面喷砂后涂无机富锌漆，μ=0.35。

所需螺栓个数为110.2/31.5=3.5，取4个。

本题目次梁为Q235，主梁为Q325，故查《钢结构设计规范》表7.2.2-1时，取μ=0.35。

单项选择题 A3型题

男婴2个月。高热2天，继之体温不升，反应差，拒奶，时有尖叫，间断抽搐，查体：面色青灰，皮肤黄染，唇发绀，双眼凝视，前囟饱满，心肺无异常，腹较胀，脐部红肿。

为明确诊断，最有意义的检查是（）

A.脑电图

B.脑超声波

C.脑脊液检查

D.血胆红素

E.血清钙测定
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单项选择题

Should we care if over 150 known species of animals have (91) from the earth in the last fifty years Should we be concerned that there are (92) thousands of species whose very existence is (93) endangered—largely because of our activities (94) , after all, is the natural end of populations. Species are born, then (95) , and then die. Some live a (96) time, perhaps millions of years; some die more quickly. We have (97) the extinction of many species we know about, and we have undoubtedly sealed the (98) of others. In fact, there are undoubtedly many other species that have lived among us during our time on earth, but that have disappeared as a (n) (99) of our activities without our ever having known they existed.
It is hard to explain the rationale of many of us who are concerned about such matters. I have never seen a sea whale, (100) I don’t want them to become extinct. Moreover, I felt this way long before I understood anything about how they might be an important part of an ecosystem. Possibly such feelings merely reflect the cultural attitude that it is "nice" to wish other living things well; thus, the attitude is (101) . I feel nice.
There are, of course, more rational reasons for (102) the extermination of any species. For one thing, the kind of attitude that encourages or sanctions the destruction of other species is a threat (103) our own wellbeing. If such an attitude exists, we ourselves might (104) victim to it. living things (including us) might be expected to fare better where there is (105) for life. The extinction of other species could also threaten us (106) by simplifying the system of which we are a part or by destroying parts of the ecosystem (107) which we directly rely. For example, if we continue to poison the oceans (108) we are willing to believe only a few bottom dwellers are affected, we might (109) overstep some critical threshold and trigger the wholesale death of plankton, thus finding ourselves without a major (110) of the world’s food and with our oxygen supplies dwindling.

A．for

B．to

C．at

D．with
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