above all first first of all firstly for one thing in the first instance in the first place
首先;
above all first first of all firstly for one thing in the first instance in the first place
首先;
first harmonic wave
基波,或称一次谐波;
first-harmonic resonance
基波共振,基波谐振;
基波共振,基波谐振;
First harmonic component
一次谐波分量;