复数：roofs
读音：英[ruːf]、美[ruːf]
意思：
1、n. 屋顶；顶
2、vt. 覆盖；给 ... 覆以屋顶
举例：The wind was whispering in the roof.
屋顶上风声飒飒。
用法
1、roof用作动词时意思是“给…盖上屋顶，做…的屋顶”。
2、roof只用作及物动词,接名词或代词作宾语。
3、roof的现在分词是roofing，过去式是roofed。
roofsn. 屋顶( roof的名词复数 )(1) 顶板(2)顶（巷道）有…顶的洞顶
The paper was used for sealing up holes in walls and roofs.
这些纸用来封住墙壁和屋顶的洞。
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 The Oxford English Dictionary lists "rooves" as an alternate, one of several outdated spellings used in the UK, and in New England as late as the 19th century.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。
