【英语故事】坐井观天井底之蛙来自英语故事课堂 00:00 07:17There is a frog. He lives at the bottom of a well and he never goes out of the well. He thinks the sky is as big as the mouth of the well.One day a crow comes to the
一、 钻井设备及工具1. accumulator 储能器2. active tank 循环池3. adjustable bolt (刹把)调节螺栓4. admission pipe 进气管线5. agitator 搅拌器6. air chamber空气包7. air line 气管线虫虫虫虫飞8. air-operated hoist气动绞车9. alternating current drive