Animals

• as gentle as a lamb
  нежный, ласковый

  Marion is as gentle as a lamb when she is with her baby daughter.
• as innocent as a lamb
  невинный, наивный

  Sara is as innocent as a lamb; she still believes that all people are kind and generous.
• as meek as a lamb
  послушный, кроткий как ягнёнок

  On the surface Kelly is as meek as a lamb, but I know that actually she is naughty and quarrelsome.
• get (someone's) goat
  раздражать кого-либо

  My husband is very unpunctual, and it gets my goat.
• in two shakes of a lamb's tail
  очень быстро

  "Please, wait for me. I'll be back in two shakes of a lamb's tail."
• like lambs to the slaughter
  безропотно, покорно, "как агнец на закланье"

  Our baseball players went like lambs to the slaughter to meet the best team in our area.
• separate the sheep from the goats
  отделить более компетентных людей от менее компетентных, разделить на две группы

  I am not at all sure that joining the military is a good way to separate the men from the boys.