He for nearly 20 years.
A:When; has left
B:When; has been away
C:How long; has left
D:How long; has been away
设a∈R,则a>1是1a<1的( )
下列仪器中,不属于定量仪器的是( )
已知集合M=x|0<x<3,N=x|x2-5x+4≥0,则M∩N=( )