Read aloud the text of the eighth grade English Volume II of Hebei Education Press Hebei Education Press, in Meizhou, Guangdong with this version

It seems that I didn't look at the textbook to see if there is an introduction to this aspect, saying that there are audio materials to download. If not, it means that this mp3 can't be found~

English translation
He lost his American arm but is still climbing

Alon Rolston is an American who is very interested in mountain climbing. As a climber, alon is used for adventure. It's an exciting thing to do dangerous sports. There are many times when alon almost lost his life because of an accident. In April 262003, he found himself in a very dangerous situation when climbing in Utah

Translation on page 24 of eighth grade English volume 2

Do you remember what you were doing at that time? People can always recall what they were doing when an important event happened in history. For example, many contemporaries in the United States can clearly recall what they were doing on April 4, 1968, a pivotal day in modern American history

A and B two cars from AB two opposite, 80 kilometers away from the end of the meeting. Known a and B two car speed ratio is 4:5a, B two distance how many kilometers

First of all, let's explain whether it is "meeting 80 kilometers from the midpoint."
If it's true, B is better than a when they meet: 80 * 2 = 160 km
When we met again, the travel ratio of Party A and Party B was also 4:5
Therefore, the distance between the two places is 160 / (5-4) * (5 + 4) = 1440 km

The waist length of an isosceles triangle is 2.5cm, the circumference is 8cm, and the height on the bottom is 2cm. What is its area?

The area is three square centimeters
In Pythagorean theorem 2.5 square minus 2 square, half of the bottom is 1.5 cm. The bottom is 3 cm, the bottom multiplied by the height divided by 2, and the area is 3 square cm

Given that in RT △ ABC, ∠ C = 90 °, perimeter is 36, right angle side AC = 12, calculate the area of RT △ ABC

In RT △ ABC, AB2 = ac2 + BC2, AB2 = 122 + (24-ab) 2, ab = 15, BC = 24-ab = 9. So s △ ABC = 12ac · BC = 54

The whole formula of tree planting problem
namely
There are two species on both ends
Number of trees = total length △ number of intervals-1
Total length =?
Interval number =?
Both ends are different
Number of trees = total length △ interval number + 1
Total length =?
Interval number =?
To plant at one end and not at the other:
Number of trees = total length △ interval number
Total length =?
Interval number =?

There are two species on both ends
Number of trees = total length △ number of intervals-1
Total length = (tree + 1) × number of intervals
Both ends are different
Number of trees = total length △ interval number + 1
Total length = = (tree-1) × interval number
To plant at one end and not at the other:
Number of trees = total length △ interval number
Total length = number of trees × number of intervals
Number of intervals = total length △ number of trees

If the side length of a square is increased by 3cm, the area will be increased by 39cm

Hello
The length of the original square:
（39-3×3）÷3÷2
=30÷6
=5 (CM)
Area of the original square:
5 × 5 = 25 (cm2)

If the sequence {an} satisfies A1 = 12, an = 2an-1 (n ≥ 2), then A4=______ ．

∵ sequence {an} satisfies A1 = 12, an = 2an-1 (n ≥ 2), ∵ sequence {an} is an equal ratio sequence whose first term is A1 = 12 and common ratio is 2, ∵ A4 = 12 × 23 = 4

Li Dabo, a professional fish farmer, is "resourceful". To know how many fish there are in a fish pond, he thought of an ingenious way. First, he picked up 30 fish in the pond and made a mark for each fish. Then he put them back into the pond, detoured into the water and opened in all directions. After a few days, the 30 fish were distributed in all parts of the pond, There are two marked fish. He figured out how many fish there are in the bath. Do you know how many fish there are?

It's a matter of probability. It's very simple
2/50=4%
30 / 4% = 750

Read aloud the text of the eighth grade English Volume II of Hebei Education Press Hebei Education Press, in Meizhou, Guangdong with this version