1. 凹面镜：concave lens 凹透镜 | concave mirror 凹面镜 | concave mirror reflector 凹面反光镜
2. 凹镜：concave milling cutter 凹形铣刀 | concave mirror 凹镜 | concavity 凹度
3. 凹镜,凹面镜：concave lens 凹透镜 | concave mirror 凹镜,凹面镜 | concentric capacitor 同心电容器
4. 凹形反光镜：concave lens 凹透镜 | concave mirror 凹形反光镜 | condenser 1. 聚光镜片 2. 聚光器
1. Using the sun's rays harnessed in a concave mirror is the traditional way to light the torch.