腹腔双套管负压引流的压力一般维持在()
A.2~4kPa
B.4~6kPa
C.3~4k
D.5~7kPa
E.4~5kPa
参考答案:A
With the weather getting colder, visitors from Australia spent their ___ days in Beijing.
A.a few last
B.last few
C.few last
D.last a few
绝缘臂的有效绝缘长度是多少?