业务错连常发生在SDH网络出现故障的情况下,那些故障会导致业务错连:().
A.网元失效
B.网络多处断纤
C.两网元间单纤断
D.网元外时钟丢失
参考答案:B
It often happens that people with good eyesight fail to see is right in front of them.
A.which
B.that
C.what
D.as
SARS的主要传播途径是()。
A.消化道传播
B.呼吸道传播
C.蚊虫媒介传播
D.皮肤黏膜接触传播
E.呼吸道和消化道传播