American summers are filled with outdoor picnics, baseball games and swimming pools. Summer in America is a time 小题1:________ the outdoors, no matter how hot it might be. Let’s take a look at some of the popular drinks.

Lemonade is 小题2:________ of all American summer drinks. It 小题3:________ by mixing lemon juice, water and sugar. It is usually served very cold, with ice.

Ice tea is 小题4:________ popular summer drink in America. Ice tea is usually 小题5:________ in a tall glass of ice. Many Americans 小题6:________ to add sugar to sweeten the drink. This drink is often drunk in the afternoon 小题7:_______ relaxing in the shade. Ice tea is now also sold by the bottle , at almost any store in America.

The Slurpee, a famous American drink in recent years, is a great 小题8:_______to cool off in the summer heat. It is a mix of ice, sugar and fruit juices. However, the drink is mostly made of ice. They can 小题9:_______ at most small convenient stores. Slurpees are popular with young Americans.

Milkshakes have a long 小题10:_______ in America . It is made of a mix of ice cream , milk and flavoring.

牙体长轴应解释为（）。

A.通过牙体中心的一条假想纵轴

B.通过牙冠中心的一条假想纵轴

C.通过牙根中心的一条假想纵轴

D.通过牙冠与牙根中心的一条假想纵轴

E.贯穿冠根的一条假想纵轴