架设卫星接收天线应注意什么？

(B)

Tim Richter and his wife, Linda, had taught for over 30 years near Buffalo, New York—he in computers, she in special education. "Teaching means everything to us", Tim would say. In April 1998, he learned he would need a heart operation. It was the kind of news that leads to some serious thinking about life’s purpose.
Not long after the surgery, Tim saw a brochure describing Imagination Library, a program started by Doily Patron’s foundation (基金会) that mailed a book every month to children from birth to age five in the singer’s home town of Sevier, Tennessee. "I thought, maybe Linda and I could do something like this when we retire," Tim recalls. He placed the brochure on his desk, "as a reminder."
Five years later, now retired and with that brochure still on the desk, Tim clicked on imagination library. The program had been opened up to partners who could take advantage of book and postage discounts.
The quality of the books was of great concern to the Richters. Rather than sign up online, they went to Dollywood for a look-see. "We didn’t want to give the children rubbish," says Linda. The books-reviewed each year by teachers, literacy specialists and Dollywood board members-included classics such as Ezra Jack. Keats’s The Snowy Day and newer books like Anna Dewdney’s Llama series.
Satisfied, the couple set up the Richter Family Foundation and got to work. Since 2004, they have shipped more than 12,200 books to preschoolers in their area. Megan Williams, a mother of four, is more than appreciative "This program introduces us to books I’ve never heard of."
The Richters spend about $400 a month sending hooks to 200 children. "Some people sit there and wait to die," says Tim. "Others get as busy as they can in the time they have left.\

Why did the Richters go to Dollywood

A. To avoid signing up online.
B. To meet Dollywood board members.
C. To make sure the books were the newest.
D. To see if the books were of good quality.

设f(x)=x²+ax+b，A={x|f(x)=x}={a}，由元素(a，b)构成的集合为M，求M。

阅读下面的诗词，根据提示完成赏析。(7分)

春夜闻笛^①

唐 李益

寒山^②吹笛唤春归，迁客相看泪满衣。

洞庭一夜无穷雁，不待天明尽北飞。

采桑子^③

南宋 朱敦儒

扁舟去作江南客，旅雁孤云。万里烟尘，回首中原泪满巾。

碧山相映汀洲冷，枫叶芦根。日落波平，愁损辞乡去国人。

注释：①李诗是诗人谪迁江淮时所作。②寒山，今江苏徐州市东南，是东晋以来淮泗流域战略要地，屡为战场。③周必大在《二老堂诗话》说朱敦儒“靖康离乱，避地自江西走二广” 。

（1）两首诗传情达意都借助了“雁”这一意象。李诗借大雁春来北飞，言迁客欲归不得（雁归而人留），寄喻得体，衬托有方。朱诗                                     。(3分)

（2）两诗中都有一“泪”字，但抒发的情感并不相同，请简要分析。(4分)

延时断开常闭触点的图形符号是（）。

A、A

B、B

C、C

D、D

胸膜腔内压是由下列哪项因素形成

A．大气压-非弹性阻力

B．大气压-弹性阻力

C．大气压+弹性阻力

D．大气压-肺回缩力

E．大气压+肺回缩力