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 er 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.