8. If you don't tell me the reason, I won't leave => Unless 9. If I weren't so tired I would join you there. => Unless 10. Our sources of energy will soon end if other sources are not found => Unless

`8.` Unless you tell me the reason, I won't leave.

`9.` Unless I were so tired, I would join you there.

`10.` Unless other sources are found, our sources of energy will soon end.

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$\text{Điều Kiện 1: }$ If + S + V(s/es)/tobe + O, S + will + V.

$\text{Điều Kiện 2: }$  If + S + Ved/were + O, S + would/could + V.

`-` Unless + câu khẳng định (`+`) `=` If + câu phủ định (`-`) : Nếu không