Now he is as gentle as a lamb!

他温顺得就像小羊羔！

She's as gentle as a lamb.

她像小羊羔一样温顺。

Mr. A does not make a fuss; he is as gentle as a lamb.

先生不爱争吵抱怨，他是十分温和的人。

Our dog barks viciously at strangers, but it's as gentle as a lamb with the children.

我家的狗见到人就狂吠，但跟孩子们在一起时却十分老实。