最大和最小的病毒分别是什么？
最大的病毒是天花病毒，最小的病毒是黄热病毒。
Has ____ how many spies we caught during the war ____ up to now?
A．it been declared; have been set free
B．it declared; have been set free
C．they declared; has been set free
D．they declared; have set free
外墙柔性腻子所有试验样品及基材应在标准试验条件下放置至少（）。
A、12h；
B、24h；
C、36h；
D、48h。
