complment
(1)余
(2)补
(3)补码，补数
(4)补图

• external photoelectric effect
• external quatum effieciency
• external screw thread
• external transmittance
• extinction
• extinction angle
• extinction coefficeint
• extinction coefficient
• extinction meter
• extinction radtio
• extinction ratio
• extinction test
• extinction voltage
• extinquishing filter
• extra-axial imagery
• extra-axial object point
• extra-axial point
• extra band
• extra central telescope
• extraction
• extraction ability
• extra=dense barium crown
• extra dense flient
• extra excitation
• extra-fine fit