下列部位的口腔粘膜上皮有角化,但不包括( )。
A.牙龈
B.硬腭
C.唇红
D.舌腹
E.舌背
参考答案:D
There was plenty of time. She ______ .
A.mustn’t have hurried
B.couldn’t have hurried
C.must not hurry
D.needn’t have hurried.
坐标法主要借助于平面直角坐标系来实施。