NUL
发表于 2025-3-30 11:24:13
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爵士乐
发表于 2025-3-30 15:52:35
Work, Energy and Power loads by burning oil or petrol. People can do similar jobs, for example lifting cases into the boot of a car. In order to do this, they must take in energy by eating food. If we were unable to get this ‘food energy’, or . as scientists call it, we could not work and we would grow weaker and weaker.
过分自信
发表于 2025-3-30 18:35:39
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Lobotomy
发表于 2025-3-30 23:12:09
Reflections and Shadowsh a narrow slit in front of it, the light is easily seen where it falls on a surface, for example a sheet of paper (Fig. 15.1). The bright line across the paper from the slit marks the path of the ray, which is a straight line.
啜泣
发表于 2025-3-31 04:35:56
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