他继续解释他的理论，父母们将会有更多孩子当婴儿死亡率是高的，以便确保若干孩子将能生存下来去照顾他们当他们变老了。
He continued by explaining the theory that parents will have more children when infant mortality is high, so as to ensure that several children will survive to take care of them as they grow old.
他继续解释他的理论，父母们将会有更多孩子当婴儿死亡率是高的，以便确保若干孩子将能生存下来去照顾他们当他们变老了。
He continued by explaining the theory that parents will have more children when infant mortality is high, so as to ensure that several children will survive to take care of them as they grow old.
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