How subject and object pronouns work

Every English pronoun has two forms: one for when it does the action (subject), and one for when it receives the action or follows a preposition (object). Here's the full set:

Subject	Object
I	me
you	you
he	him
she	her
it	it
we	us
they	them

The rule is straightforward: if the pronoun is performing the verb, use the subject form. If something is being done to it, or it comes after a preposition (with, for, to, about, between…), use the object form.

✅ She called him after dinner. ❌ Her called he after dinner.

She is doing the calling → subject form. Him is being called → object form. Swapping them sounds obviously wrong here, but the mistakes get sneakier in other structures.

Where learners actually slip up

The biggest trap is compound subjects and objects — sentences with "and" or "or" joining two people. When another name is involved, even native speakers hesitate.

❌ Me and Tom went to the cinema. ✅ Tom and I went to the cinema.

Quick test: remove "Tom and." You'd never say "Me went to the cinema," so I is correct. The same test works for objects:

❌ The teacher asked Tom and I to stay. ✅ The teacher asked Tom and me to stay.

Drop "Tom and" — "The teacher asked I to stay" is clearly wrong. You need me. Many B1–B2 learners overcorrect here because they've been told "me and Tom" is rude, so they start using "I" everywhere, even where me is the right choice.

After prepositions — always the object form

Any pronoun that follows a preposition must be in the object form, no exceptions:

✅ This secret stays between you and me. ❌ This secret stays between you and I.

"Between you and I" is one of the most common errors in English — you'll hear it from native speakers too. But between is a preposition, so it demands me.

Other examples:

✅ She sat next to him. ✅ They couldn't do it without us.

After "be" — the formal vs. real-life split

Technically, a pronoun that follows be (is, was, were…) should be in the subject form, because it refers back to the subject:

"Who's there?" — "It is I."

In practice, almost nobody talks like this. In everyday English, you'll hear and read:

"It's me." / "That was him."

For exams and formal writing, know the "correct" form (It is I / It is she). In conversation and informal writing, the object form after be is standard and accepted. Most grammar tests at B1–B2 level won't penalise "It's me," but they will test whether you know the difference in other positions.

One more thing to watch

Don't confuse they/them used as a plural with they/them used for a single person whose gender you don't know:

✅ Someone left their bag here. I'll return it to them.

This is standard modern English. The pronoun follows the same subject/object pattern — they for the subject slot, them after a verb or preposition — regardless of whether it refers to one person or several.

Keep the test simple: find the verb, ask who is doing it (→ subject pronoun) and who is it happening to (→ object pronoun). If there's a preposition in front of the pronoun, object form wins every time.