读短文，用所给动词的适当形式填空。
Have you seen dolphins? Dolphins are interesting animals. Scientists have found they are very smart.
Although they don't have hands, they can solve problems by using tools, just like us. There is no evidence
that dolphins have a language of their own, but they can understand many sign languages. They can always
give quite correct and quick responds. Amazing, isn't it? Dolphins live in a very different world, but they
can do our "intelligent (智力) tests" easily. Are you interested? Please go and see by yourself.
读上边的材料，完成下边的短文。
Dolphins are interesting animals and researchers find them are very smart. They 1_____ (have) no hands,
but can use tools 2_____ (solve) problems, just like us. There is no evidence that dolphins have a language
of their own, but they can 3_____ (understand) many sign languages. They are always 4_____ (give) quite
correct and quick responds. Dolphins live in a very different world, but they are good at 5_____ (do) our
"intelligent tests".