How "to be" works in the present

English has one verb that refuses to follow the normal rules: be. Most verbs take at most two forms in the present tense (walk / walks), but be has three: am, is, and are. Which one you use depends entirely on the subject.

Subject	Form
I	am
he / she / it	is
you / we / they	are

That's the whole system. No other verb in English does this, so there's nothing else to memorise — just these three forms matched to their subjects.

What "be" actually does

You reach for be whenever you want to link a subject to a description, an identity, or a state — not an action.

✅ She is a software engineer. ❌ She are a software engineer.

✅ I am tired after the meeting. ❌ I is tired after the meeting.

Notice that there's no "doing" in either sentence. Nobody is running, cooking, or deciding anything. The verb simply connects the subject (she, I) to what follows (a software engineer, tired). That connecting job is why grammarians call be a linking verb.

You'll also meet be as a helper inside other structures — progressive tenses (I am reading), passives (The door is locked) — but in every case, the same am/is/are rule applies to the present.

Contractions and when to skip them

In everyday speech and informal writing, native speakers almost always contract:

• I am → I'm
• you are → you're
• he is → he's
• it is → it's

The negative contracts too: is not → isn't, are not → aren't. One odd gap: "amn't" doesn't exist in standard English. Say "I'm not" instead.

✅ I**'m not** ready yet. ❌ I amn't ready yet.

In formal or academic writing, keep the full forms. In a quiz or conversation, contractions are perfectly fine.

The mistakes that actually catch people

1. Mixing up is and are with tricky subjects. When a sentence starts with there, the verb agrees with the noun that comes after it, not with there itself.

✅ There are two problems with this plan. ❌ There is two problems with this plan.

B1–B2 learners often default to there is regardless of number because it sounds natural — and honestly, many native speakers do the same in casual speech. In careful English, though, match the verb to the noun: two problems is plural, so you need are.

2. Dropping "be" entirely. If your first language doesn't use a copula (Russian, Arabic, and many others omit it), you may produce sentences like She tired or They engineers. English always requires the verb:

✅ They are engineers. ❌ They engineers.

3. Confusing it's and its. This isn't strictly a "be" error, but it surfaces constantly when practising is. It's = it is. Its (no apostrophe) = possessive. If you can expand the word to it is and the sentence still makes sense, use the apostrophe.

✅ It's cold outside. (It is cold outside.) ❌ Its cold outside.

A quick self-test trick

Whenever you write a sentence with be, mentally swap the subject for a pronoun and check the table. "My brother and I" → we → are. "The report" → it → is. If the form matches, you're good. If it doesn't, fix it before moving on. That single habit will eliminate most errors with this verb.