gadfly|gadflies

他在公司会议上总是扮演牛虻的角色，不断质疑管理层的决策。

He always acts as the ___gadfly in company meetings, constantly questioning management decisions.

牧场的牛群被牛蝇叮咬后显得很烦躁。

The cattle on the ranch became restless after being bitten by ___gadflies.