许多当地企业都参与了这次慈善活动。

Many local ___firms participated in this charity event.

这块面包外皮很硬，但里面很软。

The ___firm crust of the bread contrasts with its soft inside.

这张桌子很稳固，不会轻易摇晃。

This table is ___firm and doesn't wobble easily.

她坚定地摇头拒绝了对方的邀请。

She gave a ___firm shake of her head to decline the invitation.