And crucially, voidable only at the option of the person who lacked capacity.

关键在于，只有缺乏行为能力一方才有权选择是否撤合同。

Voidable so they can get out of it.

可撤，此他们可以解合同。

And the key takeaway, the headline rule, is that contracts entered into by these folks are typically voidable.

关键要点，规则是：这些人所订立合同通常是可撤。

A contract is voidable if a party lacked the mental ability to understand the nature and consequences of the transaction.

如果一方缺乏理解交易性质和后果精神能力，合同可被撤。

If the mistake goes to the essence of the agreement and has a material effect, the contract may be voidable.

如果错误涉及协议内容并产生实质性影响，合同可能是可撤。