1 一般在词尾加S,如 open- opens
2 以辅音字母加Y 结尾,把Y 改为I 再加ES ,如 carry - carries
3 以 s ,x ,o ,sh ,ch 结尾加ES ,如 pass- passes ; fix - fixes ; wash - washes ; watch - watches
4 不规则变化：
have - has
be - is
加油!不明白再问!