"Unless"の使い方

Unlessif...notと同じです。 ifのように、unless の後には現在形、過去形、過去完了形(決して条件付きではありません)。 Unlessは、すべての条件文でif...notの代わりに用いられます。unlessを使った文節の順序に決まりはありません。

仮定法現在:Unless + 現在形
Ifを用いて Unlessを用いた言い換え
You will be sick if you don't stop eating. You'll be sick unless you stop eating.
I won't pay if you don't provide the goods immediately. I won't pay unless you provide the goods immediately.
If you don't study dilligently, you'll never understand trigonometry. Unless you study dilligently, you'll never understand trigonometry.
仮定法過去: Unless + 過去形
Ifを用いて Unlessを用いた言い換え
If he wasn't very ill, he would be at work. Unless he was very ill, he would be at work.
I wouldn't eat that food if I wasn't really hungry. I wouldn't eat that food unless I was really hungry.
She would be here by now if she wasn't stuck in traffic. She would be here by now unless she was stuck in traffic.
仮定法過去完了:Unless + 過去完了
Ifを用いて Unlessを用いた言い換え
Our director would not have signed the contract if she hadn't had a lawyer present. Our director would not have signed the contract unless she had had a lawyer present.
I wouldn't have phoned him if you hadn't suggested it. I wouldn't have phoned him unless you'd suggested it.
They would have shot her if she hadn't given them the money. They would have shot her unless she'd given them the money.