大家好，我是小典，我来为大家解答以上问题。potato的复数，roof的复数很多人还不知道，现在让我们一起来看看吧！
1. The plural of roof is roofs or rooves. "Rooves" is an older form of the word and rarely used these days. Australian children right up to the 1980s, for example, were brought up with the word "rooves" rather than roofs, and it is still an accepted form in Australia today (though uncommon). Also, despite New Zealand English developing from UK English, it should be noted that in NZ, the plural of roof is rooves, in both its written and spoken form.
2. The accepted plural is "roofs". The Oxford English Dictionary lists "rooves" as an alternate, one of several outdated spellings used in the UK, and in New England as late as the 19th century.
语法规则如4楼所言，不再重复。但根据上面的资料看，也就是说，两种拼写在英语里都可以，只是roofs现在更常见，rooves老外也能明白，属于过时的拼法。考试时应该不会真考这种有争议的题。练习还可以接受。
PS：老师也是人，而且语言是很灵活的东西。看得出你是个学习较真儿的人，但向老师指正时态度应委婉些为好。
本文到此讲解完毕了，希望对大家有帮助。