reserve; spare; replacement; alternate;standby;backup(美) 你在那兒看見的那架巨型噴氣機一定是總統(tǒng)的(波音)707~座機。The jumbojet you saw there must be the Presidential backup 707./~方案alternate scheme (or proposal)/~機器standby machine/~金reserve fund/~款項reserve fund/~輪胎spare tyre