Please let me know, when we should add es or s to an action verb to convert a base form into a third person singular form? I meant to ask are there any finger tips we can follow?


go = goes

Walk = walks

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    I think you mean "rules of thumb." – Obfuskater Jul 17 '14 at 3:13

Keep in mind that there are both regular and irregular verbs. If we just go by the examples you've provided, we could hypothesize that the "s" ending follows a (regular) verb root that ends with a consonant and "es" goes with a (regular) verb root that ends with a vowel--usually an 'o'. Verbs that end with 'y,' like "to fly" become "flies." Verbs that already end with an "e" just need an 's' to conjugate in the third person. I'd say that those are decent rules of thumb.


Obfuskater gave sound rules of thumb. Here are slightly fuller guidelines:

For the third person singular we use the –s form of the verb: Luke seems happy.

Spelling of the –s form

-e is added before –s in verbs ending in a sibilant sound (represented by the letters -s, –ss, -z, -sh, -ch and –x) and in a single –o (but not those ending in –oo):

hiss/hisses, buzz/buzzes, wash/washes, catch/catches, box/boxes, go/goes
but: boo/boos

In verbs with word-final single –s, some writers double the final –s of the first form before adding the –e; this is optional:

gas/gases or *gasses, focus/focuses or focuses

With verbs ending in –y following a consonant, we change the –y to –i and add -es, but if the word-final –y follows a vowel/diphthong sound, we simply add –s:

carry/carries, try/tries but: play/plays, employ/employs


The final –(e)s of this form is pronounced:

/s/ after unvoiced consonants (except /s, ʃ, ʧ/: /kɪks, pʊts, kɒfs/).

/z/ after voiced consonants (except /z, ʒ, ʤ/), vowels and diphthongs: /hʌgz, siːz, leɪz/

/ɪz/(or/əz/) after /s, z, ʃ, ʒ, ʧ/ and /ʤ/: /bɒksɪz, bʌzɪz, wɒʃɪz ruːʒɪz, kæʧɪz, ʤʌʤɪz/


One verb, BE. is completely irregular in the unmarked tense: I am, he is, we/you/they are.

One verb, HAVE. has an irregular third person singular form: /hæz/.

Two verbs, DO and SAY, have pronunciation changes in the third person singular form: do, does /duː, dʌz/, say, says /seɪ, sez/

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    Apart from the two irregular verbs be and have, this is the same as the rule to make plural nouns from singular ones. – tchrist Sep 8 '15 at 5:22

Irregular verbs — those that end with x, z, ch, sh, ss and o — we can add es. Verbs ending with y but followed by a consonant, we should remove y and add ies.

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    This answer has already been given. New answers should add something new. But understand that those aren’t irregular. Be and have are irregular. The others are just differently regular. – tchrist Sep 8 '15 at 5:21

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