牙釉质细胞外基质蛋白主要有以下几大类().
A.釉原蛋白
B.釉蛋白
C.非釉原蛋白
D.蛋白酶
E.非金属蛋白酶
参考答案：A, C, D
Questions 27-30
A． It is a new one with only 2 editors.
B．It takes him on the permanent staff.
C．It controls the final look of his works.
D．It has a nurturing environment.
单机不准挂下列哪些车辆？（）
A、超限货物的车辆
B、液化气体的车辆
C、装载鲜活物资的车辆
D、关闭截断塞门的车辆
