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“Get up, get up, Jim. It's time to get up!” My mother said while she was pushing me. I opened my eyes and looked at the clock. “Oh dear! It's a quarter past eight already.” I'll be late for school again,” I thought. I jumped out of the bed, washed my face, and then hurried to the bus stop without breakfast. As soon as I got on the bus, it started running. “I'm sure I can get to school in time,” I said to myself. Suddenly the bus stopped. The bus driver got off the bus, then got on the bus again and said, “I'm sorry, ladies and gentlemen. There's something wrong with the bus. Please get off the bus and wait for another one.” “I couldn't wait. The school isn't far. I'd better run to school,” I thought, and then I began to run. But before I got to school, it began to rain hard.
I reached the classroom but I was wet shivering with cold. The math teacher had already begun his lesson. It was Mr. Smith. He was very strict with his students and the students were a little afraid of him and so was I. I liked neither him nor his math lessons. I hesitated (犹豫) for a moment, and then I opened the door. “I'm very sorry, Mr. Smith. I'm late again,” I said with a red face.
“It's you again, Jim,” Mr. Smith said angrily, “I've told you not to be late, but you...” he suddenly stopped and looked at my wet clothes. He turned to the class and said, “I'm very sorry, boys and girls. ” With these words he quickly took off his own jacket and handed it to me. “Now, take off your wet coat and put on this one or you'll catch cold,” he said kindly.
I went to my seat with Mr. Smith's jacket on. It was a bit larger for me but I felt very warm in it. I found, for the first time, math was so interesting and how well I could understand it!
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的一个单调递增区间为( )