我在地面上作了標(biāo)記，然后為了確保起見(jiàn)步測(cè)了一下。I marked the ground and then paced it out to be sure.我估計(jì)這大廳有80米長(zhǎng); 我來(lái)步測(cè)一下.I think the hall is 80 metres long; I'll pace it.先步測(cè)20英尺,再在地上做出標(biāo)記.Step off twenty feet and then place a marker in the ...