TOM is not having been trained as a dancer is her own regret

TOM's not having been trained as a dancer is her own regret.第一is应该是写错了吧,用所有格形式才通顺.TOM's not having been trained as a dancer 做名词,是主语.翻译为,tom因自己没被训练成一个舞蹈员而后悔.
被训练就用 be trained,现在完成时,就是have been trained了.
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