英语翻译
a second class of SI units comprises the derived units,many of which have special names.Table
1-4 is a list of those we shall find most useful in our work in this book.The radia(symbol rad)is a supplemental unit in SI for a plane angle.Aseries of names and symbol to form multiples and submultiples of SI units has been established to provide an alternative to the writing of powers of 10.Table A-1 includes these prefixes and symbols.