a hermit crab造句

• He ' s like a hermit crab
  他就象个寄居蟹
• Hermit crabs have rear parts that are not protected by their own shell . for protection , a hermit crab backs into the unoccupied shell of a marine snail . when it outgrows its home it looks for a larger shell and moves in
  寄居蟹的身体下半部并没有天然的外壳保护，因此需要找一个空的螺壳寄居，当日渐长大，螺壳再容身不下时便迁往另一个更大的家。