Angle认为咬合的关键牙齿是
A．下颌第一恒磨牙
B．下颌第二恒磨牙
C．上颌第二恒磨牙
D．上颌第一恒磨牙
E．下颌第三恒磨牙
参考答案：D
For many years, the principle goal of computer (73) was to write short pieces of code that would execute quickly. The (74) needed to be small, because memory was expensive, and it needed to be fast, because processing power was also expensive.
A．users
B．programmers
C．that
D．program
病害的基本基本概念：
