At a glance
Verb る べくもない means "there is no way to " or " is out of the question". It is a formal, written expression for something that cannot possibly be done, known or hoped for.
Verb (dictionary form) + べくもない
彼が何を考えていたのか、今となっては知るべくもない。 Now there is no way to know what he was thinking.
How to form it
Attach べくもない to the dictionary form of the verb:
| Verb group | Example | With べくもない |
|---|---|---|
| う-verb | 知る, 望む | 知るべくもない, 望むべくもない |
| る-verb | 比べる | 比べるべくもない |
| する | 理解する | 理解すべくもない (理解するべくもない is also seen) |
| 来る | 来る | Rarely used |
Only the ending changes for tense and politeness. The verb stays in dictionary form:
| Form | Plain | Polite |
|---|---|---|
| Present | 望むべくもない | 望むべくもありません |
| Past | 望むべくもなかった | 望むべくもありませんでした |