sucking mouth parts

例句：

1. 1. The dog is always trying to suck the food out of my hand.
   狗总是试图从我的手中吸走食物。
2. 2.The baby was sucking on his mother's breast when he fell asleep.
   宝宝在入睡前正在吸吮他的母亲的乳房。
3. 3.The scientist studied the behavior of animals by observing their sucking mouth parts.
   科学家通过观察动物的吸吮行为来研究它们的习性。