属于主承托区
A．上颌前部牙槽嵴顶B．磨牙后垫C．切牙乳突D．腭小凹E．上颌后部牙槽嵴顶
参考答案：E
— Would you please help me with my spoken English?
— ________. Practice makes perfect.
A．That's all right
B．No problem
C．Quite well
D．No, thanks
报告文学的写作，首先必须（）
