正常人的面色是（） A.明润含蓄 B.青如翠羽 C.赤如鸡冠 D.黑如乌

This is Jim. He is thirteen. He is from the USA. He is a student. He has a good friend. His name is Jack. Jack is twelve. He is from Canada. Jack is tall but Jim is short. They are in the same class, Jim is in Class Two. Jack is in Class Two, too. They go to school(上学) at seven in the morning and go home(回家) at six in the afternoon.

根据短文内容，选择正确答案。

小题1:Jim and Jack are ____.

A．sisters

B．friends

C．teacher and student

D．from the same country(国家)小题2:Jim is ____.

A．short

B．tall

C．strong

D．big小题3:Jim and Jack are in ____.

A．the same class

B．different grades

C．the same color

D．the same family小题4:Jack is in ____.

A．Class 4

B．Class 3

C．Class 2

D．Class 1小题5:They go to school at ____ in the morning.

A．6:00

B．7:00

C．7:30

D．8:00

设N_A代表阿伏加德罗常数的数值，下列说法中正确的是

①常温常压下，17 g甲基（—¹⁴CH₃）所含的中子数为9N_A

②常温常压下，22.4 L NO气体的分子数小于N_A

③56 g铁与16g硫充分反应，失去2N_A个电子

④常温常压下，100 mL 0.5 mol/L的乙酸溶液中，乙酸的分子数目小于0.05N_A

⑤标准状况下，22.4 L二氯甲烷所含有的分子数为N_A

⑥常温常压下，1 mol氦气含有的核外电子数为4N_A

⑦1mol/LNaCl溶液表示1L水中含有NaCl 58.5g

⑧1molO₂与足量金属钠反应，得到了4mol e‾

⑨不同物质的量浓度硫酸等体积混合后，溶液物质的量浓度变为原来和的一半

⑩1 mol Na₂O₂晶体中含有阴离子总数为N_A

A．①②⑧

B．③④⑨

C．②④⑩

D．⑤⑥⑦

感觉平面有助于判断病损部位，可据体表判定受损节段，下腹壁反射对应的脊髓反射中枢位于哪个节段（）

A.T5-6

B.T7-8

C.T6-7

D.T9-10

E.T11-12

重整新氢中断如何处理？

灯泡破碎时，炽热的灯丝有类似火花的危险作用。