一个是单数，一个是复数。单数grape在前面有表示单个物体的冠词/代词（a, the, that, this...), 或者后面有单数形式的动词(is)时用。复数grapes在前面有复数形式代词(those, these)或者后面有复数形式动词（are)时用。
grape双语例句
1、The colouring pigments from the skins are not allowed to bleed into the grape juice.
外皮上的色素不能渗到葡萄汁里面去。
2、The grape vine climbed up along the wall.
葡萄藤沿墙攀缘而上。
3、Grape Valley where the mountain field around the monuments for the Jieshi Shan another meet.
葡萄沟所在的山场周围，为碣石山中的名胜古迹又一荟萃之地。
4、The grapes will soon be ripe. let&39;s speed up our preparations for the grape harvest.
葡萄快熟了，得上紧准备收摘了。
5、The storm has blasted our grape.
暴风雨毁了我们的葡萄。
