fly变三单

flies

1.一般现在时，第三人称单数做主语时，动词的变化规则。
1）一般在动词后加-s词尾。如，come-comes live-lives
2）在以ch, sh ,s, x, 或o结尾的词后要加-es, 如，
teach-teaches catch-catches wish-wishes wash-washes
miss-misses guess-guesses mix-mixes fix-fixes
go-goes do-does
3）以“辅音+y”结尾的词，先变y为I 再加es,如，
Try-tries study-studies reply-replies fly-flies

另外这里也介绍了的说：
http://www.myspaces.com.cn/?CH=Log&ArticleID=37473

flys

辅音+y 结尾，变第三人称单数直接加s

flys