aboard: 在船(或飞机,车)上。如:I never went aboard a ship.
broad: 为形容词,宽广的。如:He has very broad shoulders.
abroad: 副词,在国外或海外。如:He often goes abroad.
board: 为动词,上(船,飞机,车)。如:The passengers are boarding the plane now.
这三词都与电有关
electrical: 多指本身不产生电,但是与电有关的。如:electrical engineering(电机工程);an electrical transcription(广播唱片)
electric: 着重于发电的,电动的或导电的。如:electric generator(发电机);electric light(电灯)
electronic: 电子的,电子操作的。如:electronic engineering(电子工程学)