Preposição = Uso de By

Diferentes usos de BY:
usamos by em muitas expressões para dizer como algo foi feito. Por exemplo, se diz:
send something by post
do something by hand
pay by cheque/by credit card.
Ou sobre algo que possa acontecer by mistake, by accident, by chance;
usamos também antes de meios de transporte, para dizer como alguém viaja:
by car,
by train,
by plane,
by boat,
by ship,
by bus,
by bicycle;
and,
by road,
by rail,
by air,
by sea,
by underground.
Obs:
não dizemos by my car mas sim in my car;
ex.: I come by car; he didn´t come by the car in their car but by the taxi in a taxi.