书城教材教辅科学读本(英文原版)(套装1-6册)
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第254章 第三册(79)

"He preys on living insects-slugs, grubs, worms, and snails. He swallows his prey whole. The sharp teeth in the upper jaw are to help him to hold his slippery prey, while he swallows them. They are not meant for chewing or tearing.

"But his great tongue is his fly-trap. It is always covered with a thick, slimy fluid. As sure as a fly comes within reach, the slimy tongue darts forward like lightning, and never misses its prey."SUMMARY

The frog can live in the water as well as on the land. His hind feet are webbed for swimming. His body is always cold. He has teeth in the upper jaw only. The root of his tongue is in front ; he can throw it forward a long way, to catch the insects and grubs, which are his food.

Lesson 26

Air

"Norah, hand me the water bottle, please," said Fred. "Be careful; it is full of water. Thank you. Now, if I poured the water out of the bottle, what would you say about the bottle then?""I should say the bottle would be empty," said Norah.

"Ah, that"s just what I should have said till today," said Fred. "But it is not empty. Is it, Will?