下列物質(zhì)的鑒別方法中正確的是（ ）

A．MnO2和木炭——觀察顏色

B．CO2和N2——燃著的木條分別伸入瓶中

C．Ca（OH）2溶液和稀鹽酸——取樣，滴加碳酸鈉溶液

D．NaOH溶液和Na2CO3溶液——取樣，滴加酚酞試液

A young woman carrying a three-year-old child got on a bus. The conductor hurried to give her a warm welcome and then kindly asked the other passengers to make more room for the woman and her child. On seeing this, people began to talk. "You know this conductor used to be very rude. Now suddenly he has changed his bad behavior, "said a middle-aged man.
"Yes, he should be praised and we must write a letter to the company," said a second passenger. "That's right," another lady said, "I wish a newspaper reporter were here so that more people could learn from this conductor.”
Just then a gentleman who looked like a teacher turned to the conductor and said, "Excuse me, but can I know your name, please? Your excellent service must be praised..."
Before he could open his mouth, the three-year-old child sitting on the young woman's lap interrupted, "I know his name. I call him Dad."
【小題1】
One passenger suggested writing a letter to the company to ______  .

A．make a demand for more buses	B． thank the conductor for his good service
C．criticize the conductor for his rude behavior
D．invite a newspaper reporter to write about the conductor

【小題2】
What was the gentleman?

A．A teacher.	B．A newspaper reporter.
C．Not known from the story.	D．The conductor's friend from his company.

【小題3】
. The word "he" in the last paragraph refers to _______.

A．the gentleman	B．the conductor
C．the middle-aged man	D．the three-year-old child

【小題4】
It is clear from the story that the conductor _______.

A．has changed his attitude towards his work

B．has now been kind and polite to all passengers

C．has not changed his rude behavior to passengers

D．has now been kind and polite to women with children

如圖所示，空間分布著寬為L，垂直于紙面向里的勻強(qiáng)磁場．一金屬線框從磁場左邊界勻速向右通過磁場區(qū)域．規(guī)定逆時針方向?yàn)殡娏鞯恼�方向，則感應(yīng)電流隨位移變化的關(guān)系圖（i-x）正確的是

如圖所示，空間分布著寬為L，垂直于紙面向里的勻強(qiáng)磁場．一金屬線框從磁場左邊界勻速向右通過磁場區(qū)域．規(guī)定逆時針方向?yàn)殡娏鞯恼�方向，則感應(yīng)電流隨位移變化的關(guān)系圖（i-x）正確的是

如圖所示，空間分布著寬為L，垂直于紙面向里的勻強(qiáng)磁場．一金屬線框從磁場左邊界勻速向右通過磁場區(qū)域．規(guī)定逆時針方向?yàn)殡娏鞯恼�方向，則感應(yīng)電流隨位移變化的關(guān)系圖（i-x）正確的是

珠江三角洲曾遭遇“咸潮”，水源中含氯量高達(dá)7100mg/L，遠(yuǎn)遠(yuǎn)超過正常值250 mg/L。以下說法正確的是（   ）

A．“咸潮”中氯離子濃度可達(dá)0.2mol·L—1

B．自來水廠可加入適量AgNO3溶液除去Cl—

C．自來水廠可用蒸餾法來凈化水

D．直接用“咸潮”水作為水源，對人體無害

如圖，在中，分別是的中點(diǎn)，若，Co則  cm．

如圖，在中，分別是的中點(diǎn)，若，Co則  cm．

如圖，分別以△ABC的兩條邊為邊做平行四邊形，所做的平行四邊形有____   __個；
平行四邊形第四個頂點(diǎn)的坐標(biāo)是              .

如圖，已知□ABCD中，點(diǎn)M是BC的中點(diǎn)，且AM=6，BC=12，CD=4，則該平行四邊形的面積為             .