珀西对兰花的痴迷可以回溯到1951年。Percy's enchant-ment with orchids dates back to 1951.这个城镇的历史可回溯到中世纪.The history of the town dates back to the Middle Ages.注意:我们还要回溯所忽略的字符.Note that we back up over ignored characters too....
Dogs love splashing in mud and hippos wallow in it.狗喜欢在泥水洼里扑腾，河马则喜欢在其中打滚撒欢儿。Hippos are unable to submerge in the few remaining water holes.在仅剩的几个水坑里，河马根本无法没入水中。hippos wallowing in the river在河里打滚的河马...