牛病毒性腹泻-黏膜病的传染源包括BVD病畜和持续性感染牛。
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牛病毒性腹泻-黏膜病的特征性病变是食管黏膜糜烂、溃疡大小不等呈直线排列。
A. 对
B. 错
Who will ________ the meeting tomorrow?
A. bid
B. host
C. take
D. hold
The Winter Olympic Games, like the Summer Olympic Games, ________ held every four years.
A. is
B. will be
C. are
D. was
The key password must be ________ the key store password.
A. put to
B. set to
C. held to
D. got to
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