It will help you better understand tenses , prepositions , and all the other parts of speech we normally take for granted .

知晓另一种语言让我们可以比较，有助于更好地理解时态，介词，还有那些我们通常想当然的语法成分。

His prosthesis works by using two electrodes that make contact with the skin on his upper arm . When he tenses a muscle , tiny pulses of electricity from the nerves beneath the electrodes cause the hand to close ; when he tenses another , the hand opens .

他的假肢使用两个电极与上臂的皮肤相连接，当他绷紧一块肌肉时，电极下的神经所产生的微小的电流脉冲使得手掌握紧，绷紧另一块肌肉时可以使手掌伸开。