若集合A={（x，y）|y=x+3}，B={（x，y）|y=-2x+6，则A∩B

一带正电的质点，电荷量q=2×10^-9 C，在静电场中由a点移到b点，在这过程中除电场力外，其他力做功为6×10^-5 J， 质点动能增加了8×10^-5 J，则a、b两点间的电势差φ_a-φ_b为 [ ]

A．3×10⁴ V

B．1×10⁴ V

C．4×10⁴ V

D．-1×10⁴ V

妊娠期高血压疾病的病因有（ ）、（ ）、（ ）、（ ）、（ ）、及（ ）。

How many people have I met who have told me about the book that they have been planning to write but have never yet found the time? Far too many．

This is Life, all right, but we do treat it like a rehearsal （排演) and, unhappily, we do miss so many of its best moments．

We take jobs to stay alive and provide homes for our families, always making ourselves believe that this style of life is merely a temporary state of affairs along the road to what we really want to do． Then, at 60 or 65, we are suddenly presented with a clock and several grandchildren and we look back and realize that all those years waiting for Real Life to come along were in fact real life．

In America they have a saying much laughed at by the English：“Have a nice day!” They speak slowly and seriously in their shops, hotels and sandwich bars． I think it is a wonderful phrase, reminding us, in effect, to enjoy the moment: to value this very day．

How often do we say to ourselves, "I'll take up horse-riding （or golf, or sailing) as soon as I get a higher position," only to do none of those things when I do get the higher position．

When I first became a reporter, I knew a man who gave up a very well paid respectable job at the Daily Telegraph to go and edit a small weekly newspaper． At the time I was astonished by what appeared to me to be his completely abnormal （反常的) mental state． How could anyone turn his back on Fleet Street in central London for a small local area？I wanted to know．

Now I am a little older and possibly wiser, I see the sense in it． In Fleet Street the man was under continual pressure． He lived in an unattractive London suburb and he spent much of his life sitting on Southern Region trains．

小题1:The first paragraph of the passage tells us that           ．

A．we always try to find some time to write a book

B．we always make plans but seldom fulfill them

C．we always enjoy many of life's best moments

D．we always do what we really want to do小题2:The underlined phrase "turn his back on" （paragraph 6) most probably means       ．

A．leave for

B．return to

C．give up

D．rely on小题3:The man （ paragraph 6) left his first job partly because he was           ．

A．in an abnormal state

B．under too much pressure

C．not well paid

D．not respected小题4:What is probably the best title for the passage?

A．Provide Homes For Our Family

B．Take Up Horse-riding

C．Value This Very Day

D．Stay Alive

向某溶液中加水稀释，该过程中不发生变化的是（　　）

A．溶质的质量

B．溶液的质量

C．溶质的质量分数

D．溶质的密度

享受优惠退回的增值税税额均不缴纳企业所得税，但出口退回的消费税税额应征收企业所得税。( )