( )的文书仅限在独立的组织中传达。
A．前行文 B．后行文 C．内行文 D．外行文
参考答案：C
________ repeatedly, the problem still appeared in the beginners’ homework.
A．Explaining
B．Having explained
C．Having been explained
D．To be explained
与宫颈癌发生有关
A．黄曲霉霉素B．3,4-苯并芘C．EB病毒D． * * 状病毒
