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更多“LL（1)中的“1”通过求FIRST、得到。 （)”相关的问题
设有下列文法Gi： (1)G1：A→AaB｜bB B→Dc D→Ad (2)G2：S→aABbcd｜ε A→ASd｜ε B→PC｜SAh｜ε C→Sf｜Cg｜ε ①计算上述文法中的每个非终结符的FIRST和FOLLOW集合。 ②证明上述文法是否为LL(1)文法？说明为什么？ ③若不是LL(1)文法能否改写？构造LL(1)分析表。
听力原文：M: What is your expected salary？
F: Since this will be my first job, as for salary, I would leave it to you.
M: Would you accept a starting salary at ＄1 200？
F: I think it is reasonable. I will accept it.
M: Besides, you'll also enjoy life insurance and one-week paid holidays every year.
F: Mm, that sounds nice. Thank you very much.
How much does the man offer the woman？
A．＄1 200.
B．＄ 2 100.
C．＄120.
High Dive
kilometers up into the atmosphere.(1). No one has ever leapt from such a height or gone supersonic without an airplane or a spacecraft. Yet Stems, an airline pilot, is not the only person who wants to be the first to accomplish those feats. Two other. have people an Australian man and a Frenchman, are also planning to make similar leaps.
(1). First, she'll climb into a cabin hanging from a balloon the size of a football field. Then the balloon will take her high into the's trato sphere -- the layer of Earth's atmosphere 12 to 50 kilometers above the planet. "The ascent will take two and a half to three hours." said Stems.”Tll be wearing a pressurized, temperature-controlled space suit.”
At 40 kilometers, Stems will be able to see the gentle curve of Earth and the blackness of space over head. Then she'll unclip herself from the cabin and dive headfirst, like a bullet, into the atmosphere.(3) For high dive, astronaut escape suits are a key to success. Current pilot and astronaut escape suits are guaranteed only a maximum altitude of 21 kilometers. Del Rosso, a NASA engineer of spacesuits and life — support systems, said the suit designed for Stem's jump could serve as a model for the lethal environment of higher climbs.(4)
The first hazard is oxygen-deficient air. Any person without an additional oxygen supply at 40 kilometers would die within three to five seconds. The second hazard is low atmospheric pressure. Atmospheric pressure is much lower at high altitudes than it is at sea level. The low atmospheric pressure of the upper stratosphere causes the gases in body fluids to fizz out of solution like soda bubbles.(5)Other hazards include temperatures as low as 55 degrees Celsius, flying debris, and solar radiation.
For Stems to survive, her spacesuit will have to protect her from all of these hazards. "A spacesuit is like a one-person spaceship," Del Rosso explained. "You have to take everything you need in a package that's light enough, mobile enough, and tough enough to do the job. You can't exist without it."
feat n. 技艺的表演
stratosphere n. 同温层
pressurize v. 加压，增压
lethal adj. 致死的
fizz v. 嘶嘶响
debris n. 碎片
A. It will handle several major hazards.
B. Escape suits are tough enough to stand the atmospheric pressure of the upper stratosphere.
C. From there, she'll take a death-defying leap back to Earth at supersonic speed.
D. "In 30 seconds, I'll be going Mach speed," said Stems.
E. How will Stems make her giant jump？
F. In short, blood boils.
t/s | 0 20 30 40 50 60 70 80 |
c(t)/g·m-3 | 0 3 5 5 4 2 1 0 |
物料流量qV=0.1m3·s-1。若该反应在CSTR中进行，在同样
听力原文：Man: Jean, have you got that report all typed up？
Woman: Not yet, Mr. Black. Mrs. Brown asked me to type some letters for her. I'll finish pretty quickly and then I'll start on that.
Man: Don't forget I need it first thing in the morning. I have to take along to Chicago to the regional meeting.
Woman: Don't worry, I'll get it done. My husband is on a business trip, too. He's in Detroit today, and tomorrow he'll be in Boston. So I'm planning to stay late. After it's typed up I'll leave it on your desk. It should be finished by 8:00.
Man: I'm sorry to keep you so late.
Woman: It's all right, Mr. Black. Really, I don't mind at all. Besides, I can use a little extra money. My husband's birthday is next month. I want to buy him a new watch.
Man: What kind are you going to get him, a Bulova？
Woman: No, I thought I'd get a Rolex, or an Elgin. I don't really know much about watches.
Man: I've got one of those Seiko digitals. I really like it.
Woman: Do you think my husband would like one like that？
Man: I'm sure he would.
Woman: If they're that good, I will get him one.
Man: Well, at least he won't get a tie. That's what I usually get.
The woman had to type (1) first before the report.
The man will take the report to Chicago to (2) .
The woman's husband will get a new (3) on his birthday.
The man dislikes a (4) as birthday gift.
(1)
达稳态后，dex/dt=0,求:(1)反应速率-dcA/dt的-般表达式(式中不含X项);(2)k2》k3的反应速率简化表达式:(3)k3＞＞k2的反应速率简化表达式。
