化简21+log23=______.
∵2log23=3,
∴21+log23=21?2log23=2×3=6,
故答案为:6.
When asked why he went there, he said he was sent there __________ for a space flight.
A.training
B.being trained
C.to have trained
D.to be trained
吸入性肺脓肿()。
A.多为单发病灶,以段叶分布
B.常为多发病灶,两肺外带多见
C.肺部病变继发感染所致
D.肺结核空洞继发感染
E.肺脓肿直接蔓延