Since, for и ago: как правильно говорить о времени

Since, for и ago связаны со временем, но каждый отвечает на свой вопрос.

Since = с какого момента?

Since ставится перед точкой начала: since Monday, since 2021, since breakfast, since I moved here.

I have lived here since 2021.

For = как долго?

For ставится перед периодом или длительностью: for two hours, for six months, for a long time.

I have lived here for three years.

Ago = сколько времени назад?

Ago ставится после периода и указывает на завершённое событие в прошлом. Обычно используется Past Simple.

I moved here three years ago.
She called ten minutes ago.

Сравните

I started this job two years ago.
I have worked here for two years.
I have worked here since September 2024.

Все три предложения могут описывать одну ситуацию с разных точек зрения.

Типичные ошибки

I live here since three years. → I have lived here for three years.

I have met him two days ago. → I met him two days ago.

I’ve been here since five hours. → I’ve been here for five hours.

Практика

1. We’ve known each other ___ 2019.
2. I’ve been waiting ___ twenty minutes.
3. He left half an hour ___.
4. She has worked remotely ___ last summer.

Ответы: since; for; ago; since.

Подсказка: since — начальная точка; for — длительность; ago — сколько времени назад произошло завершённое событие.