water level ga[u]ge
(1)水位表
(2)水准仪

• background limited infrared photoconductor
• background luminance
• background luminescence
• background noise
• background projection
• background radiation
• background signal
• background wave
• backing
• backing-off
• backing paper
• backing sheet
• backlash
• Backlight and Components
• back lighting
• back-off
• back-out
• back over
• back-pack camera
• backplan
• back projection
• back-reflection Laue photograph
• back-reflection photograph
• back resistance
• back-roll