蛇吐信的样子着实很可怕。那一伸一缩的舌头好像随时都在准备攻击一样。要是有谁说蛇的舌头根本无害，估计没有人会相信。然而大自然总是那么爱捉弄人……

    Snakes don't sting or use theirforkedtongues as weapons. The tongues are perfectly harmless.

    A snake sticks out its tongue to collect data for its Jacobson's Organ, an organ strategically located in front of the roof of the snake's mouth that functions as a chemical receptor. Each and every time the snake flicks out its forked tongue, it snares chemicalparticlesin the air, which latch onto, or dissolve in, themoistureof the snake's tongue. Once the snake reels in its tongue, it inserts the tips of the forked tongue into the two awaiting openings of the Jacobson's organ where the particles, especially those of animal body odors, are identified, analyzed, and acted upon.

    For the male snake, the tongue is both a sensory organ, and a sensual organ. The tongue plays a vital role in snake courtship and reproduction, as the male snake'sjerkingbody motions and rapidly flicking tongue either charms the female snake, or renders her unresponsive. In either instance, by sticking out their tongues, snakes ensure the survival of their species.

    forked 叉子似的

    particles 微粒

    moisture 湿气

    jerking摇晃