A:In the way; whe
B:All the way; which
C:In the way; what
D:All the way; /
凸透镜的焦距为13m,凹透镜的焦距为12m,把它们作为眼镜镜片,镜片度数为φa和φb.则( )
1.8的2.7倍加上10.92除以8.4的商,和是( )