The Japanese Macaca monkey has been studied in the wild for over 50 years. In 1952, on one small Japanese island, scientists dropped some   26  in the dirt for the monkeys. The monkeys liked their taste, but they found the dirt   27 .

One clever 18-month-old monkey found she could   28  the problem by washing the sweet potatoes in a nearby river. She taught this to her mother. Her   29  also learned this new way and they taught their mothers, too.

All the younger monkeys   30  learned to wash the dirty sweet potatoes to make them   31  to eat. But many old monkeys found it very hard to learn this and still ate the   32  sweet potatoes.

Then something very surprising   33 . In the autumn of 1958, scientists found that the monkeys on other nearby   34  began washing their sweet potatoes too. Scientists still don’t fully understand how this knowledge was   35  from one island to another.

Which city is         , Beijing or Shanghai?

This piece of music sounds ________.

Do you have a dog? I have a cute   41 . It’s my birthday present (礼物)   42  my uncle. Its name is Maria. It’s an   43  dog. It is big and it is yellow in color. It likes running and jumping (跳跃). It   44  playing ball games with me. It’s great fun   45  with it. Maria is very   46 . It can play basketball. It is a basketball star in my neighborhood. Can it put the   47   into the basket (篮框)? Yes, it can.   48  does it do it? It uses (使用) its head (头). Maria is really good at it. All my friends like to   49  it play basketball. I’m   50  to have it. It brings me more friends. It is funny, too. It can dance to the music. What a lovely dog!

Do you have a dog? I have a cute   41 . It’s my birthday present (礼物)   42  my uncle. Its name is Maria. It’s an   43  dog. It is big and it is yellow in color. It likes running and jumping (跳跃). It   44  playing ball games with me. It’s great fun   45  with it. Maria is very   46 . It can play basketball. It is a basketball star in my neighborhood. Can it put the   47   into the basket (篮框)? Yes, it can.   48  does it do it? It uses (使用) its head (头). Maria is really good at it. All my friends like to   49  it play basketball. I’m   50  to have it. It brings me more friends. It is funny, too. It can dance to the music. What a lovely dog!