虛擬語氣:'不可能'假設

與現在相反

條件句：過去式（were）

主句：would+動詞原形

If I were you I would not be such scheming.

與將來相反

條件句：should/were to+動詞原形

主句：would/should/could/might+動詞原形

If it should be clear day tomorrow,I would bath my dog.

與過去相反

條件句: had +動詞過去分詞

主句:would have +動詞過去分詞

If I had known you are such scheming,I would not have trusted you.

虛擬語氣:愿望, 請求,建議，命令....

Wish

對現在的愿望: wish +動詞過去式

I wish my neck don’t ached.

對過去的愿望wish + had/would have +動詞過去分詞

I wish I had protected my neck from indisposition.

對將來的愿望: wish + should/would/could/might/ +動詞原形

I wish my neck could cured.

demand, suggest,insist, order...+should +動詞原形