为了防止羊群过度繁殖，牧羊人定期给公羊去势。

The shepherd regularly ___castrates the male sheep to prevent overbreeding.

农场主决定将这只公羊阉割，因为它比普通公羊更温顺。

The farmer decided to castrate the ram to make it a ___wether, as it was calmer than ordinary rams.