natural crossing的用法和樣例：
例句
- Former chicken of black blood chicken plants forest is by pure Hei Yu pheasant and the distinctive chicken that form after grouse is natural and copulatory are planted.
叢林黑血雞原雞種是由純黑羽山雞與野雞自然交配后形成的獨特雞種。 - Hybrids are produced by the unnatural crossing of two species.
雜交種是由兩個物種非自然雜交產生的。
