The structure of couplers should be updated continuously with the increase of train weight and speed.

车钩结构要随着列车重量和速度的提高而不断更新。

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If you want to lose weight or gain muscle, you need to train hard for weeks on end to see results.

如果你希望减轻体重或者增长肌肉，你需要去刻苦地训练几周然后才能看到结果。

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Now she hits the gym five to six days a week to weight train and run.

CNN: Mom's last words inspire 85-pound loss

Current designs for maglev trains rely on electromagnets, since nobody has been able to make a permanent magnet strong enough to lift the weight of a train.

ECONOMIST: Maglev trains

So it comes down to this: if half the increase in efficiency demanded by the new CAFE requirements is to come from further improvements in the power-train, then the other half will have to come from reductions in a vehicle's weight.

ECONOMIST: Tech.view: Unbearable lightness? | The