dull dullness
(1)钝的
(2)黯淡
(3)模糊的

• hill cloud lens
• Hilllger centring device
• hinge
• histogram
• hlaf-transmitting mirror
• H-like ion
• hob
• hodoscope
• Hoffmann's prism
• holding circuit
• holding device
• hole
• hole basis
• hole-basis system
• hole burngin
• hole burning
• hole-burning effect
• hole-burning model
• hole carrier
• hole conductivity
• hole-couping
• hole density
• hole-drilling system
• hollow axle
• hollow-cathode