题干

能在pH=2的无色溶液中大量共存的一组物质是( )

A:NaCl    CuSO4     KNO3

B:AgNO3     Na2SO4    KCl

C:K2CO3   NH4NO3   MgCl2

D:Al2(SO43 NaNO3 NaCl

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D

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    Every city, in fact, can be felt by its warmth-not in terms of its natural climate but its human touch.

    About twenty years ago, I arrived in Australia. Searching for a place in a map in the street, I was approached by an elderly man who asked “How are you? Are you lost? How can I help you?”, which really impressed and warmed me. Another time, as I was pushing my bike on the sidewalk one night, a young lady shouted to me: “Carry me please” and then jumped onto my bicycle. While we had a little chat, she got where she wanted and hopped off my bike with “Thanks, bye!” At that moment, I had a sense as much of pleasant surprise as of “being trusted”.

    Still in Australia, two of my friends decided to hitch(搭便车)their way to Sydney in order to save money. A young driver stopped, and luckily he was also going to Sydney, so he let them in and even allowed them to drive while he went to sleep on the back seat. About eight hours later, they arrived and he woke up. Saying thanks to each other, they went their separate ways.

    In my opinion, no matter how developed and advanced it is, if in general a place presents itself with a cold and indifferent(冷漠的)face to people, especially to strangers, even keeping them highly alert(警惕的)not to be cheated all the time, can perhaps hardly be classified as a land of civilization(文明). In a sense, the attitude towards strangers that the people have in the city mirrors its warmth.