angthing有复数形式吗？
单数。
anything是不定代词，作主语时谓语动词要用单数。
1、常用不定代词有：some（something,somebody,someone,somewhere）,any（anything,anybody,anyone,anywhere）, no（nothing,nobody,no one）, every（everything,everybody,everyone,everywhere）,all,each,both,much,many,（a）little,（a）few,other（s）,another,none,one,either, neither等.
2、如果主语是some（something,somebody,someone,somewhere）,any（anything,anybody,anyone,anywhere）, no（nothing,nobody,no one）, every（everything,everybody,everyone,everywhere）,each,a (little), another,none,one,either 等时,谓语动词用单数形式.
3、如果主语是all,both, all, others 等时谓语动词用复数.
grass(名词复数)
grass
[英][grɑ:s][美][græs]
n.草，青草; 草地，草坪; 告密者; 〈俚〉龙须菜;
vt.用草覆盖; 使…长满草; 使…吃草;
vi.渐渐被草覆盖; 放牧;
第三人称单数：grasses过去分词：grassed
复数：grasses现在进行时：grassing过去式：grassed
例句:
1.
Then he finished cutting the grass.
他修整完了整片草地。
2.
Killing off phytoplankton would be like removing all grass from land.
杀光浮游植物就和把陆地上的草全拔了一样。