One day, a baby snail found that he had to carry a big and heavy shell at any time. He didn’t _________   why it was, so he went up to his mother and asked, “Why was I born with a shell that grew so _________ and heavy?” His mother said, “Because we don’t have _________ to hold us up. We can only move slowly, so we need a shell to _________   us.”

The baby snail asked again, “The caterpillar (毛毛虫) has no bones, and she can’t move quickly either. Why can she _________   without a shell?” The mother snail answered, “That’s because a caterpillar will become a butterfly. She can _________ high into the sky. The sky can protect her. ”

The baby snail had one more _________, “But the earthworm moves like us. He has no bones and he won’t turn into a butterfly. Why doesn’t he carry a hard and heavy shell?” His mother said, “He can dig a hole and hide in the _________, and then the earth can protect him.”

The baby snail then cried, “We are so _________   ! We have no protection from the sky or from the ground!” His mother smiled at him. “That’s why we have a shell. My dear, imagine that if we don’t have the shells, what will happen to you? Hot sun will dry out our bodies and we’ll have nowhere to sleep. What’s more, we’ll die in the heavy rain. How __________ it is! We don’t depend on the sky or the ground for protection. We should depend on ourselves.”

2 . Special Delivery

One day, I found my neighbors’ mail in my mailbox. I thought that was _________. I went down the street, trying to put their _________ into their mailboxes. Then I _________ that the mail in their mailboxes also had the wrong address.

I was not sure what to do when I watched a dog _________ the mail box with mail in his mouth. He _________ the mail in the box and put his stack(一叠)in. He pushed the door _________ with his nose, picked up the new stack of mail he had _________ from the box and ran down the street.

It turned out that the dog _________ Henry, the mailman in charge of mail _________ in our area. Henry has a trained dog Ada who __________ went with him on his rounds. Ada had been __________ to put mail in and take mail out of the boxes. But Henry died suddenly of a serious illness a few days ago. Henry lived alone and when he __________, no one thought to check on his dog. When Ada got loose, he continued to undertake his __________.

Ada would approach each mail box along the street, open the mailbox door with his __________, put some mail in, meanwhile take some mail out and then close the door. That was the __________ Ada used to do with Henry, who was always pleased with the dog.