We all need to look for ways to reduce our carbon footprint.我们都需要寻求降低碳排放量的方法。Perhaps the footprint was a hallucination.脚印可能只是幻象。We saw no houses, no smoke, no footprint, no boats, no people.我们没看到房子和炊烟, 也没看到足迹 、 船和人....
他此刻正在南美旅游观光。He's touring South America at this moment in time.最好是乘坐旅游巴士或骑自行车观光。Sightseeing is best done either by tour bus or by bicycles.观光巴士已经取代了火车。Tour buses have replaced railway cars....
按一般标准衡量, 地核是由相当致密的物质组成的.Judge by ordinary standards, the core is made of rather dense stuff.地球的中心是地核,地核的周围是地幔.The earth has a core and a mantle around it.一般认为地核至少是外核由镍和铁构成.The earth's core, at least the outer one is...