题目

（2009·赤峰）向装有一定量Ba(OH)2溶液的小烧杯中，不断慢慢滴入稀H2SO4至过量，有关溶液pH和滴入稀H2SO4体积的变化情况如下图所示，其中正确的是    （    ）    答案：D解析:在没加硫酸前Ba(OH)2溶液pH>7，滴入稀H2SO4后pH逐渐变小，稀H2SO过量后pH变成小于7. This is a story  that happened 15 years ago but it has always stayed with me since then.On the way back from work every evening,more often than not there would be a homeless man standing at the exit of the freeway.He always waved at every car,he was always happy and smiling and sometimes almost dancing.Every day after work when I got there，I would quickly roll down my window and give him the coins.Occasionally the red light would be on for a minute and we would ask each other about our day.His answer would always be the same，“I’m blessed！”. It amazed me that even in his situation of being homeless he was so positive，and his answer would remind me of how blessed I was.A single mother of four amazing kids,with a place to call home and with a job to provide for my kids.Then one day I was called into my boss’s office and was told that I was being laid off due to the economy.Needless to say that on my was home that day I was very sad and upset.I didn’t remember to look for my spare change and keep it ready like I usually did.I wasn’t feeling the joy as I got off the ramp where the homeless man would be.Yet there he was as alway，as l turned the ramp.He set his eyes on me，while still smiling and waving at others. While I was waiting for the red light to turn，he strolled over to my car.He had a big smile he looked me straight in the eyes and said “today I will give you a dollar”.He then reached into his pocket and pulled out a dollar bill.I was blown away.I burst into tears.I wanted to jump out of my car and hug him！ You see that day he gave me more than a dollar bill，he taught me a valuable lesson.No matter  what material things are taken  from you，no one can take away your choice to be joyful. What is the passage mainly concerned？ A.A dollar bill from a homeless person. B.A blessing coming from a homeless person. C.A woman who lost her job due to the economy. D.A homeless man standing at the exit of the freeway. From the lst paragraph，we know the homeless man is         . A.optimistic        B.brave         C.Iazy          D.kind-hearted After leaving the boss’s office，the author         . A.felt relaxed to get rid of the tiring job B.still felt joyful when coming off the ramp C.took it for granted that she was fit for her job D.didn’t put some change aside to give to the man The underlined phrase“blown away”in the 3rd paragraph most probably  means          . A.completely defeated               B.wholly blown down C.really amazed                         D.murdered by gunfire It can be inferred from the passage that         . A.material things are the most important in life B.people should be encouraged to beg by smiling C.the author’s ride home that dog was smooth sailing D.we should wait others’help when faced with challenges