短文填空 (注意适当形式)

     To many people, American food means____ , hot dogs and fried chicken. If you like sweet (甜的)____ , you may even think of apple pies (苹果派) or chocolate cookies (曲奇饼干). It's true that Americans often____ hese things.

     It's hard to find another traditional American food except (除.....之外) Thanksgiving ____ . The United States is a land of people who come from____ countries.  When the people come to America, they____ their cooking styles with them, too. So in America you can find other countries'____ . For example, they____ Italian pizzas, Mexican tacos and Chinese egg rolls. However, these foods in American aren't quite____ the original (原先的) ones in other countries.

亚洲西南与非洲相连,二者之间的分界线是  (    )

已知圆台的上、下底面半径分别是2、6，且侧面面积等于两底面面积之和．

（1）求该圆台母线的长；

（2）求该圆台的体积．

下列各图中和分别表示两种不同元素的原子，其中表示混合物的是（  ）