Gastropods

文章大意

这篇雅思听力Part4是动物学讲座，介绍腹足动物（俗称蜗牛和蛞蝓）。内容涵盖其无脊椎动物特征、5亿年前的化石、肌肉足与黏液痕迹、齿舌取食器官、外壳大小从矮蜗牛到罗马蜗牛、壳的左右旋向及肋纹刺毛等形态差异，以及多数种类以腐烂植物、真菌和藻类为食的习性。

题目与答案

1. Evolution

   · minerals in the bodies of gastropods are like in the 31_____ .

   · fossils date back 500 million years

   答案：sea

   原文定位：the minerals in their body fluids are very similar to the mineral composition of the sea

   同义替换：「like」↔「very similar to」

2. Physical features

   · single, muscular foot

   · radula (used for feeding)

   · size: British shells range from 1.5-50 mm

   · form: most shells coil to the 32_____ .

   答案：right

   原文定位：the majority coil to the right

   同义替换：「most」↔「majority」

3. · some shells have ribs, spines or 33_____ .

   · they have various colours and patterns

   答案：hairs

   原文定位：Then some shells, for instance, the plated snail, have regularly spaced ribs, while the prickly snail has prominent spines;There are even a number of species with hairs on their shells

4. Feeding habits

   · mainly feed on rotting plants, fungi or algae

   · some eat live animals, e.g. shield slugs eat 34_____ .

   答案：worms

   原文定位：the shield slug feeds on worms

   同义替换：「eat」↔「feed on」

5. Predators

   · birds, frogs, flies

   · humans - snails were probably introduced to Britain as food in the 35_____ .

   答案：1st century

   原文定位：It was the Romans who probably first introduced edible snails into Britain during the 1st century, and they are still eaten today

6. · many gastropods have particular types of 36_____ itself slippery, e.g. glutinous snail makes.

   答案：defenses

   原文定位：to protect themselves, gastropods have often developed special defenses

   同义替换：「particular」↔「special」，「types」↔「special」，「protect」↔「defenses」

7. Habitats

   · gastropods prefer dampness and shade

   · 37_____ conditions are worst

   答案：dry

   原文定位：both very hot and very cold weather is bad for gastropods, but dry conditions are the least favorable

   同义替换：「worst」↔「least favorable」

8. · biggest variety is found in old, natural habitats, e.g. 38_____ and meadowland.

   答案：forest

   原文定位：So for instance, long-established forests usually support more species than newer plantations of trees, and old natural meadowland is much better than land which has recently been farmed

   同义替换：「old」↔「long-established」，「biggest variety」↔「support more species」

9. · highly specialized species live in unusual habitats, e.g. blind snail lives entirely below the 39_____ .

   答案：ground

   原文定位：the blind snail spends its whole life buried under the ground

   同义替换：「lives entirely」↔「spends its whole life」，「below」↔「buried under」

10. · good indicators of the quality of the 40_____ .

    答案：environment

    原文定位：they are a reliable indication of how healthy our environment is

    同义替换：「good」↔「reliable」，「quality」↔「how healthy」