赤毛のアン2章12

She was sitting there waiting for something or
somebody and, since sitting and waiting was the
only thing to do just then, she sat and waited
with all her might and main.

with all one's might and main:一生懸命に

その子はそこに座って何かを、誰かを待っていた。そ
の時は座って待つしかなかったので、一生懸命座って
待っていたのだ。