男性也有生物钟，不过与女性不同，但这并不意味着他们一辈子都有生育能力。
Men have a biological clock too. It is not the same as for women but they can 't wait forever to have children.
今天的观念需要练习三、四次，每次最多不超过一分钟，练习的方式亦与先前有所不同。
The exercises for today, which should be done about three or four times for not more than a minute or so at most each time, are to be practiced in a somewhat different way from the preceding ones.
然而，利用分子钟方法所得出的不同门类起源时间总是早于化石记录，因此分子钟与化石记录的矛盾仍十分突出。
However, the origin time inferred by molecular clock is always earlier than that by the fossil record. This approach is still controversial.
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