森林涵養水源的過程及作用

森林涵養水源的過程及作用

深林儲存水源就是，在降雨的時，喬木、灌木層和草本植物層都能够截留下一部分雨水，大大減緩了雨水對地面的沖刷，最大限度地减少地表徑流.而且枯枝落葉層就像一層厚厚的海綿，能够大量地吸收和儲存雨水.這樣森林就可以儲存起大量的水，保持水土流失，在這方面就起到了重大作用.而且，當其他環境惡化，出在旱灾的時候，森林也可以利用其儲存起的水源維持其正常的生理活動，從而調節氣候~

任意7個不相同的自然數，其中至少有兩個數的差是6的倍數，這是為什麼？
我知道，這要用抽屜原理來解釋.解釋前請先字母表示的意義，寫清楚

還是不懂，能不能再講詳細一點

小王在量販店中買了單價是2.8元的某種飲料若干瓶，過了一段時間再去量販店，發現這種飲料正在進行讓利銷
每瓶讓利0.3，於是他比上次多買了2瓶，卻只比上次多花了2元錢.問上次他買了多少瓶這樣的飲料

設上次買了x瓶，則這次是x+2
2.8x=（x+2）*（2.8-0.3）-2
2.8x=2.5x+5-2
x=10
即上次是10瓶

誰有《新概念英語青少版》3B
誰有以下幾篇文章：
Lesson 43 Does anyone still knit？
Lesson 47 No laughing allowed
Lesson 53 Jonno
Lesson 59 We all need to play more

Lesson 43 Does anyone still knit？
Polly: Do you know where I can buy knitting needles，Annie？
Annie: No，I’m afraid shops like that have disappeared these days. Maybe people don’t knit any more.
Polly: I knit！I’m knitting something for my niece’s new baby！Or I will knit something for her，if I can find the right needles！
Annie: Have you tried Janner’s？
Polly: Yes，I have！I had a mad conversation with the Sales Assistant yesterday.
Annie: What happened？
Polly: I asked her where I could find knitting needles. She said they didn’t have any. I said that I always used to buy knitting needles in the first floor，next to Ladies’Fashions.
Polly: She said that Janner’s had closed that department years ago. She said，‘We don’t sell knitting needles now. Nobody asks for them any more.’
Polly: I said，‘You’re mistaken. I’m here，and I’m still asking for them！’
Lesson 47 No laughing allowed
Claire: Craig and I were in trouble at work today，Paul.
Paul: Why was that？
Claire: We laughed in the library. It’s against the rules.
Paul: What happened？
Claire: While we were entering data in the system，Craig started to laugh. When I looked at his screen，I started to laugh，too. We couldn’t stop.
Claire: We were both still laughing when the Librarian came in. he asked us what was so funny. That set us off again.
Claire: It was a story about an artist in California. He was camping in the desert when he decided to chain his legs together.
Paul: Why？
Claire: He wanted to draw them like that.
Claire: Then，while he was working on the drawing，he lost the key. There he was in the desert，with a chain around his legs. He hopped for twelve hours to the nearest town. And he took the drawing with him.
Claire: It was a pretty good drawing of two legs with a chain around them. Unfortunately，the Librarian didn’t see the joke！
Lesson 53 Jonno！
Robert: Look at that man over there. Isn’t he a singer or something？I know！He’s in that picture that you put on your ceiling！
Lucy: It’s Jonno！My favourite singer！
Robert: Quick，Lucy！Go and ask him for his autograph！
Lucy: Oh，no！I can’t！I’m too shy！Can you ask him for me，Robert？
Robert: Oh，all right.
Robert: Excuse me，sir. Aren’t you Jonno，the famous singer？
Jonno: That’s right！
Robert: I really liked the last album that you made！
Jonno: Thank you.
Robert: Can I have you autograph，please？
Jonno: Certainly. Where do you want me to sign？
Robert: Here，on the magazine，please！Thank you！
Robert: Here you are，Lucy. You’ll keep this magazine now for ever，I suppose！
Lucy: Of course！It’s got Jonno’s autograph on it！
Robert: To tell you the truth，Lucy，I don’t even know the name of his latest song！
Lesson 59 We all need to play more
Kelly: Hi，Carol！Did you go to the yoga class yesterday？
Carol: No，I missed it.
Kelly: So did I. The weather was so nice. I decided to go on the morning hike.
Carol: How was that？
Kelly: It was good. We went over the other side of the lake.
Carol: Did they walk fast？
Kelly: Not too fast，but it was fast enough for me. I’m not very fit.
Carol: Neither am I. Maybe I’ll try the hike tomorrow.
Kelly: Do you get much exercise at home？
Carol: I go to a dance class once a week. But it’s not enough. How about you？
Kelly: I walk to the bus every day. That’s not enough，either.
Carol: I ask myself how I can get more exercise in my ordinary life. But I don’t have any good ideas. Do you？
Kelly: No，I don’t，but my husband，Jed，does. He says adults don’t find time to play. He says we all need to play more. The trouble is，most of us don’t know how！

A，B兩地相距80千米，一輛公共汽車從A地出發開往B地，2小時後又從A地同方向開出一輛小汽車，小汽車的速…
A，B兩地相距80千米，一輛公共汽車從A地出發開往B地，2小時後又從A地同方向開出一輛小汽車，小汽車的速度是公共氣車的3倍，結果小汽車比公共汽車早40分鐘到達B地，求兩種車的速度.

設公共汽車速度為X千米/小時
80/X-80/3X=2+40/60
160/3X=8/3
X=160/3*3/8
X=20
20*3=60千米/小時
公共汽車速度為20千米/小時，轎車速度60千米/小時

解關於X的方程是什麼x2+（2m+1）x+m2+m=0

用十字相乘法X M
X M+1
-------------------
（x+m）（x+m+1）=0
x=—m或X=—（m+1）

A、B兩地相距950米，甲、乙兩人同時由A出發，在A、B兩地間往返，甲步行每分鐘走40米，乙跑步每分鐘跑150米，甲、乙二人第二次相遇時相距B地有多少米？

950×2=1900（米）1900÷（40+150）=10（分鐘）10×2=20（分鐘）20×40=800（米）950-800=150（米）答：甲、乙二人第二次相遇時相距B地有150米.

8.7-1.2x=3.9解方程

解
8.7-1.2x=3.9
-1.2x=3.9-8.7
-1.2x=-4.8
x=4

甲、乙兩人沿一公路自西向東前進，速度分別是3km/h和5km/h，甲於中午12點經過A地，乙於2點經過A地
則，乙追上甲要多長時間？
某水池有甲、乙、丙三個水龍頭，在同一時間內它們給水量的比是1:2:3，已知三個水龍頭齊開兩個小時後，把乙水龍頭關閉後，再用兩小時45分鐘就把池子灌滿，如果三個齊開，需要幾小時把池子灌滿.
速求

1，.下午兩點時，甲離開A地2小時2*3=6km，甲乙相距6km
設：乙x小時追上甲3x+6=5x 2x=6 x=3
離A地距離5x=15km
2.
設甲需要6X小時可以注滿，則乙需要3X，丙需要2X
根據題意得：
2*（1/6X+1/3X+1/2X）+11/4*（1/6X+1/2X）=6X
整理得：36X平方=23
設如果三個齊開時間為T則有：
T/X=6X
則T=23/6
固三個齊開需要要3小時50分鐘

7分之6化成小數後，小數點後第2011比特是什麼數位？

0.857142 857……
發現每6比特一個迴圈857142
2011÷6=335……1
所以第2011比特是8