Это грамматическая конструкция Conditionals.
Тут пример 1-го conditional.
If don't finish my homework, I won't go for a wak with my friends.
Если я не сделаю домашнее задание, то я не пойду гулять со своими друзями.
1. The weather wasn't fine last autumn.
2. Hobbit and his friends were in the mountains last winter.
3. Were <span>you at home last night? - Yes, I was.
4. </span><span>The farmhouse was old but nice.
5. </span>Liza was not in the country last month.<span>
6. </span><span>There was no letters on the table.</span>
<span>What does my father do?</span>