An adverbial modifier is a secondary par of the sentence which modifies or renders more precise a verb,an adjective or another adverb.
Adverbial modifiers of purpose,representing the reflection of the adverbial clause of the purpose on the plane of the syntax of the simple sentence.Usually,such adverbial modifiers are introduces by ‘in order to’(interpreted by some grammarians as a conjunction,introducing a final clause) as often as not reduced to the mere particle ‘to’,since it is inevitably followed by an infinitive: I went there to see my lover.
I went to his house first thing in the morning so that I may(‘might’ would show smaller probability) find him at home/for fear that I should miss him/lest I should miss him. Can be turned to:
I went to his house early(in order) to find him at home.(the purpose-part of the utterance refers to the action of the same subject)
On the other hand,if the two subjects dfiffer,only one form with the subjunctive is possible: I rang him personally,lest he should forget to call me(impossible to change into an infinitival phrase).
Adverbial modifiers of condition( a reflection of conditional clauses-not very frequent,except in a few more or less set phrase: if necessary,with perseverance, with patience, as well as in phrases beginning with “given…” which always suggests contradiction of an adverbial clause to an absolute construction: If we show enough perseverance,the matter can be solved.
Can turn into:
Given perseverance the matter can be solved.