as fierce (/tough)as a bull ❍ 有什么可怕的？他们表面上～，实际上胆小如鼠。What’s there to be afraid of? They are outwardly as fierce as a bull but inwardly as timid as a mouse.
气壮如牛
as strong as a bull 表面上～，实际上胆小如鼠outwardly as strong as a bull,but inwardly as timid as a mouse
气壮如牛qì zhuànɡ rú niú
形容气势象牛一样雄壮。as tough as bulls, fierce as a bull, strong as an ox