When you join two (or more) clauses with and, but, or or, you often don't need to repeat words that are identical in both parts. Dropping those repeated words is called ellipsis in coordination, and native speakers do it constantly. Learning to do it well makes your English sound less robotic and more natural.

The basic idea

Look at this sentence:

Tom likes coffee and Tom likes tea.

Nobody talks like that. We instinctively cut the repeated subject and verb:

Tom likes coffee and tea.

The deleted material (Tom likes) is recoverable — a listener can mentally fill it back in from the first clause. That recoverability is the whole engine behind ellipsis: if the reader or listener can reconstruct what's missing, you can leave it out.

This works with subjects, verbs, objects, and even longer stretches:

Sarah can speak French and Sarah can speak German. → Sarah can speak French and German.

We visited Paris in June and we visited Rome in July. → We visited Paris in June and Rome in July.

He wanted to help but couldn't help. → He wanted to help but couldn't.

Notice that in the last example the main verb help is dropped after the modal couldn't. This is perfectly normal and very common after modals (can, could, will, should, might).

When ellipsis works — and when it doesn't

The key condition is that the omitted words must be exactly the same in both clauses (same form, same reference). Compare:

✅ She was singing and she was dancing. — Same subject, same auxiliary. Fine.

❌ She was singing and he dancing. — Different subjects, so dropping was leaves the second clause without its own auxiliary. You need: She was singing and he was dancing.

Actually, that second sentence is sometimes heard in literary or formal English (She was singing and he dancing), but at B1–B2 level, treat it as unsafe. Stick to cutting only what is truly shared.

Another important restriction: don't delete material that would change the meaning. Consider:

I told my brother and I told my friend. → I told my brother and my friend.

This now looks like you told both people at the same time (one act of telling, two recipients). If you actually told them separately, the ellipsis subtly shifts the meaning. Context usually rescues you, but be aware of it.

The mistake B1–B2 learners make most often

Learners tend to repeat too much rather than too little. They write sentences like:

Maria enjoys reading books and Maria enjoys watching films.

A native reader finds this heavy. The natural version is:

Maria enjoys reading books and watching films.

The opposite error — cutting too aggressively — is rarer but trickier. For example:

❌ Jake has visited Spain and will Portugal.

Here a student might try to shorten it to Jake has visited Spain and will Portugal, which collapses because will needs its own verb. The two verb phrases use different auxiliaries (has visited vs. will visit), so you can't delete visit from the second one without leaving a gap. Keep both verbs:

✅ Jake has visited Spain and will visit Portugal.

A quick test you can apply

Before you delete a word, try reading the sentence with the gap filled back in. If the restored version matches what you mean — same subject, same verb form, same tense — the ellipsis is safe. If anything shifts (different tense, different subject, different meaning), keep the words in.

One last thing worth noticing: ellipsis after but and or follows the same rules as after and.

You can take the bus or you can walk. → You can take the bus or walk.

He studied hard but he failed the exam. → He studied hard but failed the exam.

In that second sentence, only the subject he is dropped because the rest of the verb phrase (failed the exam) is different from the first clause. The verb studied stays in its clause; failed stays in its clause. Only the duplicate subject goes.

Get comfortable with this, and your writing and speaking will immediately feel more fluent — not because you're adding anything, but because you're learning what to leave out.