Don't fall behind now, just when you're doing so well.你干得很出色,这个时候可别后退.Don't fall behind with your gas bill.不要拖欠煤气费.Put on a spurt, or you'll fall behind.加把劲, 不然你要落后了....

落后，下降，退后，逾期（付款等）...

fall behind的音标：fall behind的英式发音音标为：[fɔ:l bi'haind]fall behind的美式发音音标为：[fɔl bɪ'haɪnd]...