《城市污水处理及污染防治技术政策》所称“城市污水”，系指纳入和尚未纳入城市污水收集系

网络管理中的基本模型是______模型。

男性，62岁，双手DIP、PIP疼痛，偶有肿胀，晨僵10～20分钟，RF阴性，为协助诊断，应做的检查()
男性，45岁，右膝关节间断红肿、疼痛2天，查浮髌试验阳性，化验RF阴性，X线未见异常，哪项检查有助于诊断()
男性，22岁，双踝、双膝关节肿痛2年，腰痛1年，化验RF阴性，ESR轻度升高，为明确诊断应做的检查()

A．HLA-B27

B．关节液检查

C．双手X线平片

D．唇粘膜活检

E．腹部超声

下列表示物质结构的化学用语或模型正确的是（　　）

A．8个中子的碳原子的符号：¹²C

B．NaCl的电子式：

C．Cl^-的结构示意图：

D．CH₄分子的比例模型：

The trend toward smaller families may not be as modern as we think. Although women gatherers had four or five children, only two (36) survived childhood — the number found in the (37) American family today. Even our style of (38) children is starting to parallel hunting-gathering communities, in which girls and boys are permitted to play together from a young age, and consequently experiment at sex earlier and engage in (39) marriages. Clearly, we’ve moved away from the agricultural custom of arranged marriages and insulating girls at home to (40) their virginity. Moreover, the home is no longer the "place of production", as it was in farm days. We don’t make our soap, grow our vegetables and kill chickens for the dinner table. Instead, we hunt and gather in the grocery store and return to our "home base" to consume the food we have collected. No wonder we are so in love with fast food. It probably goes back to an eating strategy our primate relatives (41) over 50 million years ago. There’s no mistaking the (42) : Humans are once again on the (43) (44) . (45) By equality, I mean a more equitable division of power -- not that our roles will converge. Alike men and women have never been and never will be. (46) .

发生在井下的瓦斯爆燃速度一般不超过（）m/s。

A、50

B、100

C、150

D、500