下列哪种材料不能用作桥体的龈端
A．陶瓷
B．合金
C．复合树脂
D．热凝塑料
E．自凝塑料
参考答案：E
测验的效度是指测验的可靠性，即多次测验分数的稳定和一致程度。( )
Some teachers often give their students too much work to do, ________that they will thus improve
their school grades.
A. hoping
B. to hope
C. hope
D. hoped
