化学基本概念是化学基础知识的重要组成部分，下列各组的两个概念中，后者包括前者的是A.中和反应复分解反应B.无机物有机物C.单质化合物D.化合物氧化物

One warm day when I was walking in my backyard, I saw a pinecone(松球) on the ground. I picked it up, and some seeds fell out of it. Those seeds would be a tasty treat for a squirrel (松鼠).
I realized that pinecones were not always open like this one. Sometimes cones were tightly closed. I decided to find out why.
I gathered pinecones from my backyard. I watched them for over a year. Here’s what I learned.
Pinecones open and close slowly as the weather changes. When it’s cold or wet, cones are tightly closed. This protects the seeds inside from rain and snow.
When the weather becomes warm and dry, pinecones open. On a hot day, you might even hear the sound of cones popping open. The seeds inside may then fall to the ground. The wind may blow the seeds to places where they can grow into new pine trees. A seed has a better chance of taking root and growing when the weather is warm.
“Pine seeds are an important source of food for many animals,” says Monty Maldonado. He is a pinecone expert with the United States Forest Service. He says squirrels depend on pinecone seeds for most of their meals. They spend lots of time gathering and storing the cones. Maldonado says some animals eat only the seeds from a pinecone. But red squirrels and gray squirrels will eat the whole thing.
Small animals aren’t the only creatures that eat pine seeds. Maldonado says big grizzly bears (灰熊) and people eat them, too.
Seeds inside a pinecone are important for the growth of new trees and as food for animals. It is the pinecone’s job to protect them. So take note of the pinecones you see on the ground. They hold treasures inside.
45．According to the passage, when it is rainy, cones .
A．are open B．are usually shut C．grow quickly D．stop growing
46．According to Monty Maldonado, .
A．not all squirrels eat the whole pinecone
B．pine seeds are difficult to find for many animals
C．people in the forest are sometimes attacked by grizzly bears
D．most small animals depend on pinecone seeds for their meals
47．We can learn from the passage that on sunny days .
A．seeds may fall out of the cones
B．squirrels stay still in their nests
C．it’s difficult for a seed to take root
D．the wind will put the pine trees in danger
48．In the last paragraph, the author points out that .
A．more and more new trees need to be planted in future
B．people should be responsible for protecting animals
C．people should be careful not to damage the pinecones
D．squirrels now have few seeds to feed themselves
49．Which of the following is TRUE according to the passage?
A．The author learned why pinecones are not always open in the forest.
B．The author gathered pinecones and observed them for a month.
C．The author is fond of gathering and storing the cones.
D．Pine trees are precious to animals and people.B

(答案→)B 解析：可联系答.案.网客服索取。

我好好复习下

这个答案应该是对的

A解析分析：A、根据中和反应和复分解反应的定义分析，B、根据有机物和无机物的区别分析解答，C、根据单质和化合物的定义分析解答．D、根据酸的分类进行解答，解答：A、酸与碱作用生成盐和水的反应叫中和反应，两种物质相互交换成份生成另外两种化合物的反应叫中和反应，根据定义可以看出，复分解反应包括中和反应，故A正确，B、化合物分为有机物和无机物，有机物中含有碳元素，而无机物中不含碳元素，两者的概念应该是平行的，不存在谁包括谁，故B错误，C、纯净物包括单质和化合物，由同种元素组成的纯净物叫单质，由不同种元素组成的纯净物叫化合物，两者的概念应该是平行的，不存在谁包括谁，故C错误，D、有的酸中含有氧元素，有的酸中不含氧元素，含氧酸应该是酸中的一种，酸应该包括含氧酸，故D错误．故