周期性的的用法和樣例：
例句
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（雌性動(dòng)物的）動(dòng)情，動(dòng)情周期大多數哺乳動(dòng)物（包括人類(lèi)）的雌性產(chǎn)生的周期性的性沖動(dòng)，在此期間內雌性具有排卵的優(yōu)勢，所以該期間最適合性交；刺激
The periodic state of sexual excitement in the female of most mammals, excluding human beings, that immediately precedes ovulation and during which the female is most receptive to mating; heat.
