peck

奶奶快速地在孙子额头上亲了一下。

The grandmother gave her grandson a quick ___peck on the forehead.

农夫用一配克小麦换取了两只山羊。

The farmer traded one ___peck of wheat for two goats.

妈妈在孩子额头轻轻啄了一下，道晚安。

The mother gave her child a quick ___peck on the forehead to say goodnight.