Well we need to put by £200 for the pump valves to be renewed.我们需要存下200英镑以备更换水泵阀。The heart has valves to let blood flow in and out of it.心脏有瓣膜控制血液流进流出.The engineering gang fell earnestly to work on jammed valves.轮机组都起劲地埋...
莎草看上去和普通的草没什么两样，但其草茎是实芯的而不是空芯的。Sedge is similar in appearance to grass but has a solid rather than a hollow stem.当时的纸是由纸莎草植物的剥离物制成的.In those days , paper was made from strips of the papyrus plant.在温盖特的岛上,鹭的出现使莎草能够重现.On W...