By the time the youngest was fifteen, the mother would have been in her early fif-ties and would expect to live a further twenty years, during which chance and health made it unusual for her to get paid work.

【参考答案】

到最小的孩子15岁时，母亲就已经50岁出头，虽然还能再生活20年，但此时的机会和健康状况使得她们很难找到有报酬的工作。