颊窝毒蛇的毒牙是长的空心管子.The fangs of pit vipers are long, hollow tubes.只有四分之一的蛇具有毒液和毒牙.Venom and fangs are found in only a quarter of all known snakes.在蛇的进化史上,毒牙的出现是新的进步.A more recent advance in the evolutionary story of snakes i...
We'd be watching every plane coming in from Melbourne.我们会密切注意从墨尔本飞来的每架飞机。His trip to Melbourne had yielded a lot of information.他的墨尔本之行让他大开眼界。Other important Australian cities include Melbourne, Brisbane and Adelide...