对感染艾滋病病毒的孕产妇无偿提供预防艾滋病母婴传播的服务是A．无偿用血 B．家庭接生

Last Sunday afternoon, I was having dinner in a restaurant when my friend Poor came in. Poor is working in a bank and is quite rich, but he is always borrowing money from his friends and never pays it back. Poor saw me and came to sit at my table. He had never borrowed any money from me. When he was eating, I asked him to lend me two dollars. To my surprise, he gave me the money at once.“I have never borrowed any money from you,”Poor said,“So you can pay for my dinner.”

Read the passage and choose the best answers.(阅读短文,选择最佳答案。)

小题1:The story happened     .

A．at home

B．in a restaurant

C．in a bank

D．in an office小题2:Poor is the name of a man and the writer     .

A．knows him well

B．doesn’t know him

C．often lends him some money

D．often borrows money from him小题3:Poor is a     man.

A．busy

B．clever

C．rich

D．poor小题4:Why was Poor glad to lend the writer two dollars?

A．Because they are brothers.

B．Because Poor is rich.

C．Because the writer is rich.

D．Because Poor wanted the writer to pay for the dinner.小题5:From the story we can see     .

A．Poor is an old man

B．Poor is friendly

C．the writer paid for the dinner

D．the writer is poor

当单元式重载列车的发站是一个，而到达地区的到站有两、三个，可以循序卸车或甩下重车挂上空车时，称其为（）。

依次填入下列句子中横线上的词语，正确的一项是[ ]

①我很______，一见她的眼钉着我的，背上也就遭了芒刺一般……

②“怎么死的？——还不是穷死的？”他________的回答……

③晚饭摆出来了，四叔______的陪着。

④冬至的祭祖时节，她做得更出力，看四婶装好祭品，和阿牛将桌子抬到堂屋中央，她便_____的去拿酒杯和筷子。

A．淡然 俨然 坦然 悚然

B．坦然 悚然 淡然 俨然

C．悚然 淡然 俨然 坦然

D．俨然 坦然 悚然 淡然

实验室配制480 mL 0．600 mol·L^－1的NaCl溶液，有如下操作步骤：

①把称量好的NaCl晶体放入小烧杯中，加适量蒸馏水溶解

②把①所得溶液小心转入容量瓶中

③继续向容量瓶中加蒸馏水至液面距刻度线1 cm～2 cm处，改用胶头滴管小心滴加蒸馏水至溶液凹液面与刻度线相切

④用少量蒸馏水洗涤烧杯和玻璃棒2～3次，每次洗涤的液体都小心转入容量瓶，并轻轻摇匀

⑤将容量瓶瓶塞塞紧，充分摇匀

请填写下列空白：

(1)操作步骤的正确顺序为(填序号)       。

(2)实验室有如下规格的容量瓶：①100 mL，②250 mL，③500 mL，④1000 mL，本实验选用(填序号)       。

(3)本实验用到的基本实验仪器除容量瓶、玻璃棒外，还有       。

(4)需要使用玻璃棒的操作有       (填步骤序号)，其作用为       。

(5)误差分析：(填“偏高”“偏低”或“无影响”)

①称量NaCl时，物码倒置(1 g以下用游码)       。

②某同学观察液面的情况如右图所示，对所配溶液浓度将有何影响       。

③没有进行操作步骤④       。

④加蒸馏水时不慎超过了刻度线，立即用胶头滴管将多余的水吸出       。

⑤容量瓶中原来有少量水       。

（4分）有三种无标签的白色固体，已知它们分别是硝酸铵、氯化钾和硫酸钠，请设计方案鉴别它们，完成下表：