根尖周囊肿中正确的病理改变是
A.囊壁内衬假复层扁平上皮
B.基底层上皮细胞呈柱状,胞核呈栅栏状排列
C.囊壁内常有淋巴滤泡
D.囊壁衬里上皮无钉突
E.常含胆固醇裂隙
参考答案:E
She wants a new bike.[ ]
A. buy
B. to buy
C. bought
到目前为止,全球感染甲型H1N1流感人数占全球人口的百分比约为0.0000031,将数字0.0000031用科学记数法表示为( )