阅读短文，根据短文内容及首字母提示，在空白处填入一个适当的单词。
Three men were t__________ about the world’s greatest wonders.
The first man said, “I think the pyramids are the greatest. Though people b_______ them thousands of years ago, they are still standing. And just think: people at that time didn’t have our m_____ machines(机器). How could they build them so long ago?”
“ I a____ that the pyramids are wonderful,” the second man said, “ but I think computers are more wonderful. Everyone knows computers have changed the world a lot since people i___ them.”
Then the t_________ man said, “ I d________ with you two. I think the most wonderful thing is the Thermos(真空瓶).”
The other two men were very s__________. “A Thermos!” they said. “Why? It ‘s a simple (简单) thing.”
“Oh, no,” the man said. “In w________ you put in hot water and it stays hot. In summer you put in a cold drink and it stays cold. How does the Thermos know w__________ it is winter or summer?”