扁平苔藓的病理特征是（）

A.上皮角化层出现角质栓塞

B.上皮基底细胞液化变性及基底膜界限不清

C.上皮增生伴有异常增生

D.上皮萎缩、上皮异常增生或原位癌

E.上皮明显增厚但细胞分化较好

Beijing: The United States and North Korea had their first ________in four months here this afternoon as part of the ________negotiations on how to end North Korea’’s nuclear program, but diplomats played down prospects for________.James A. Kelly, assistant________, and Kim Yong II, North Korea’’s deputy foreign minister, met ________of formal discussions, ________on direct dialogue that began after a stormy meeting ________in which North Korea warned that it was moving quickly to ________nuclear arms.The Bush administration had insisted ________that it would only hold talks with North Korea ________because, it argued, only ________pressure would persuade North Korea to________. It got its way when North Korea dropped its insistence on ________and agreed, after extensive efforts by China, to hold unusual simultaneous negotiations with ________,________,________and ________as well as the United States.Though Bush administration officials had not ________talking privately with the North Koreans during________, the fact that Mr. Kelly and Mr. Kim met on the first day was seen as a sign of ________by the American side.