Ответ:
1. Unless your friend has an invitation, he will not be able to go to the party.
2. She will late for the lesson if she doesn't leave earlier.
3. If you are angry, they will not let you in the house.
4. He will not open the book unless he knows what tasks to do.
5. We shall have to stay home if the weather gets worse.
6. Unless you are more careful with the knife, you will cut yourself.
7. If I tell you a secret, will you promise to keep it?
8. If my mother does not have to work next weekend, we will be able to go to the funfair.
Объяснение:
Схема построения условных предложений типа First Conditional:
[If + Present Simple], + [Future Simple]
либо [Future Simple] + [If + Present Simple]
В условной части (где "если") глагол в Настоящем Простом времени, в результативной части - глагол в Будущем Простом.