《2025年快乐过暑假江苏凤凰科学技术出版社七年级提优版》

5. 解方程组:$\begin{cases}4x + y - 3z = 13, \textcircled{1} \\ 5x - y + z = 7, \textcircled{2} \\ x - 2z = 4, \textcircled{3}\end{cases}$
$\textcircled{1} + \textcircled{2}$，得 $9x - 2z = 20$，$\textcircled{4}$
$\textcircled{4} - \textcircled{3}$，得 $8x = 16$，解得 $x = 2$，
把 $x = 2$ 代入 $\textcircled{3}$，得 $2 - 2z = 4$，解得 $z = -1$，
把 $x = 2$，$z = -1$ 代入 $\textcircled{2}$，得 $10 - y - 1 = 7$，解得 $y = 2$。
故方程组的解为 $\begin{cases}x = 2, \\ y = 2, \\ z = -1.\end{cases}$

答案： 5. $\begin{cases}4x + y - 3z = 13, \textcircled{1} \\ 5x - y + z = 7, \textcircled{2} \\ x - 2z = 4, \textcircled{3}\end{cases}$
$\textcircled{1} + \textcircled{2}$，得 $9x - 2z = 20$，$\textcircled{4}$
$\textcircled{4} - \textcircled{3}$，得 $8x = 16$，解得 $x = 2$，
把 $x = 2$ 代入 $\textcircled{3}$，得 $2 - 2z = 4$，解得 $z = -1$，
把 $x = 2$，$z = -1$ 代入 $\textcircled{2}$，得 $10 - y - 1 = 7$，解得 $y = 2$。
故方程组的解为 $\begin{cases}x = 2, \\ y = 2, \\ z = -1.\end{cases}$

一 阅读理解
What will the weather be like? Some people say they can know what the weather will be like from the animals. They believe that birds, chickens and frogs can tell the weather.
When they see sea birds fly high out to the sea, they know it will be a fine day. When the weather becomes bad, the sea birds will come back to the beach. A big wind may come with a rain. They don't like to fly in the strong wind. They may sit in a tree when the rain is coming.
Some other people watch animals on the farm. When a heavy rain is on the way, chickens will not be quiet and they will run here and there. Frogs will make a big noise in the pool. If it is a nice day, the frogs will come out of the water.
1. (B) How may the weather be if sea birds fly high in the sky?
A. Cloudy. B. Sunny. C. Windy. D. Snowy.
2. (C) What will frogs do when it is going to rain?
A. Be quiet. B. Stay in water for long.
C. Make loud noises. D. Jump around the river.
3. (D) What does the passage want to tell us?
A. We should care for the animals. B. Animals don't like bad weather.
C. Different animals like different weather. D. We can know the weather from some animals.

答案： 一、【文章大意】本文主要讲述了我们可以通过动物来了解天气。
1~3 BCD

My Favourite Cat—Do Re Mi
Hello! I'm Bob. This is my little cat. I like it very much.Its name is Do Re Mi. It's very beautiful. It's gray. It has black ears, round eyes, a black nose and a small mouth. My little cat loves to eat fish and sleep a lot. One day, I saw it running after a mouse in the sitting room. About three minutes later, it brought me the mouse. "Well done, Do Re Mi!" I said happily. Then it jumped up and down and ran away. Do you like my cat? Tell me, please.

答案： One possible version:
My Favourite Cat—Do Re Mi
Hello! I'm Bob. This is my little cat. I like it very much.
Its name is Do Re Mi. It's very beautiful. It's gray. It has black ears, round eyes, a black nose and a small mouth. My little cat loves to eat fish
day, I saw it running after a mouse in the sitting room. About three minutes later, it brought me the mouse. "Well done, Do Re Mi!" I said happily. Then it jumped up and down and ran away.
Do you like my cat? Tell me, please.