Subjunctive I

Plain stem of the verb. Denotes a hypothetical action referring to the present or the future.

In simple sentences. Used in formulaic expressions to denote wish (Long live Rock 'n' roll!; Success attend you!), concession (So be it!; Come what may) and commands and requests with indefinite pronouns as subjects (Everybody leave the room!).

In complex sentences. In Nominal Clauses it's used in Subject Clauses after the expression of a modal meaning (It is required that all work hard). Rarely used after the expression of fear (His fear was that he be neglected).

In Adverbial Clauses it is used in clauses of concession after "though, although, whatever, etc." (Whatever the reason be, the fact remains) and in clauses of purpose (He stopped talking lest he be offended).