本初子午线是
A:0°纬线
B:东西半球分界线
C:南北半球分界线
D:东西经度分界线
He was very p____ with his exam results.
全集U={1,2,3,4,5,6,7,8},A={3,4,5},B={1,3,6},则(∁UA)∩(∁UB)=( )