他们没有看到门边的牌子上写着‘小心公牛’。

They did not see the sign by the gate saying 'Beware of the ___bull'.

一头公象可以重达数吨。

A ___bull elephant can weigh several tons.

在鲸群中，雄性鲸鱼通常是领导者。

In whale pods, the ___bull is usually the leader.