单项选择题

"Viruses waiting for a disease" refers to ______.

A．those viruses carried in the blood of animals
B．some viruses which are at present harmless to man
C．the viruses that reproduce in man without making him ill
D．the still-not-yet-discovered viruses in the jungle

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热门试题

单项选择题

When Dr. Causey said, We have found the loveliest diseases right in our backyard, he meant ______.

A．new viruses have just been discovered
B．his discovery was a bit frightening
C．he and his wife were surrounded by harmful viruses
D．his job was exciting

单项选择题

When the author cited the Brazilian legend he was ______.

A．trying to add a little humor
B．trying to illustrate his earlier point
C．simply joking
D．being religious