急性肾小球肾炎的严重病例常发生在起病的（） A.1～2周内 B.3～4周内 C.5～

阅读下面短文，根据短文内容判断句子的正误。正确的涂“A”，错误的涂“B”。（共5小题，每小题2分，计10分）

Long long ago, there was a girl called Nuwa. Her father was Emperor(皇帝) Yan and he loved her very much. They often played together, and she also loved her father very much. One day, she had a wonderful time. Then she swam in the sea. She was too tired to swim and she was drowned(淹死). Because she wanted to see her father then she changed into(变成) a bird. She put some stones(石头) into the sea day after day and changed the sea into the land. She made a wish, and she would like to play with her father again.

This story was a little sad. It tells something important. When we do anything, we have to work hard. Learning English is difficult but if you study hard, you can learn it well.

小题1: Emperor Yan didn’t love her daughter at all.

小题2:Nuwa put some stones into the sea when she changed into a bird.

小题3: Nuwa was too tired to swim and she was drowned.

小题4: The meaning of “land” is “操场”.

小题5:When we do anything, we don’t have to work hard.

正确诊断的第一步是（）。

A.体格检查

B.问诊

C.实验室检查

D.CT检查

E.心电图检查

已知某纯碱试样中含有NaCl杂质，为测定试样中纯碱的质量分数，可用下图中的装置进行实验。（提示：碱石灰是生石灰与氢氧化钠的混合物，可以吸收水和二氧化碳）

主要实验步骤如下：① 按图组装仪器，并检验装置的气密性

② 将10.0 g试样放入锥形瓶中，加适量蒸馏水溶解，得到试样溶液

③ 称量盛有碱石灰的U型管的质量，得到20.0g

④ 从分液漏斗滴入6mol·L^－1的硫酸，直到不再产生气体时为止

⑤ 从导管A处缓缓鼓入一定量的空气

⑥ 再次称量盛有碱石灰的U型管的质量，得到22.0g

⑦ 重复步骤⑤和⑥的操作，直到U型管的质量基本不变，为22.2g

请填空和回答问题：

（1）装置中干燥管B的作用                      _________________________。如果没有连接该干燥管，测试的结果              (填偏高、偏低或不变）。

（2）如果将分液漏斗中的硫酸换成浓度相同的盐酸，测试的结果           (填偏高、

偏低或不变）。

（3）步骤⑤的目的是                                ___________________，如果没有进行步骤⑤的操作，测试的结果________________（填偏高、偏低或不变）。

（4）试样中纯碱的质量分数为___________________。

(1～2题共用题干)男，35岁，有十二指肠球部溃疡病史，今晨突起头晕、心慌、呕血2次黑便1次，来院查：面色苍白、出冷汗、P 120次／分、BP 80／50mmHg、HCT 28％。

估计失血量为

A．200ml

B．300ml

C．500ml

D．700ml

E．1000ml

设关系模式R（ABCD），F是R上成立的FD集，F＝{A→B，C→B}，则相对于F，试写出关系模式R的关键码，并说明理由。