例句與造句

1. Before 1984, the tropical year ( not the Julian year ) and a measured ( not defined ) speed of light were included in the IAU ( 1964 ) System of Astronomical Constants, used from 1968 to 1983.
2. It is named for American astronomer Gerald Maurice Clemence ( 1908 1974 ), first scientific director of the United States Naval Observatory and professor of astronomy at the Yale Observatory, known for his work on the theory of the motion of Mars and Mercury, on the system of astronomical constants, and other research in celestial mechanics.
3. It's difficult to find system of astronomical constants in a sentence. 用system of astronomical constants造句挺難的