光学中心水平距
参考答案:装配眼镜两镜片光学中心的水平距离。
Ling Ming and Li Ling ______big eyes.[ ]
A. have both
B. both have
C. all have
D. have all
生石灰熟化时间不得少于( )天。
A.3
B.5
C.7
D.10