I 've racked my brain but I don 't know if we walked there , or got a bus or a cab .
我已经绞尽脑汁了,还是想不起来我们到底是走着去的还是做的公车还是打的车。
When graveline 's memory returned some six hours later in the hospital , he racked his brain to figure out what might have caused this terrifying bout of amnesia .