For instance:
Had I continued to advance in the field of science, especially in my linguistic knowledge and computer skills, I would have become an unrivaled pioneer in that field.
Hi again
I know the sentence above is a conditional sentence.
I am wondering which kind of conditional sentences or in which situation can be inverted such above.
I would appreciate it very much if you could elaborate your explanations or give me some source about this case.
Many thanks
The inversion you are speaking of is subject/auxiliary inversion, with deletion of if, in the condition clauses of conditional constructions:
If I had continued to advance ... ⇨ Had I continued to advance ...
The use is very similar to subject/auxiliary inversion with questions, but much more limited.
Nowadays you may invert only a small number of verbs, and these only in the ‘subjunctive’ past forms: had, were, should and could.
If I should continue to advance ... ⇨ okShould I continue to advance ...
If I were to continue to advance ... ⇨ okWere I to continue to advance ...
Inversion with other auxiliaries was common at one time—down to the early years of the 20th Century—but is no longer permitted, unless you are deliberately emulating old-fashioned speech:
If I might suggest that ... ⇨ ∗Might I suggest that ...
Could is borderline: you will still encounter Could I for If I could, but this use is rapidly vanishing.
Just as with questions, were may be inverted even if it is used as a lexical (non-auxiliary) verb:
If I were a rich man ... ⇨ okWere I a rich man...
But inversion of lexical HAVE (that is, non-auxiliary HAVE), although it was common down to the early part of the 20th Century, is no longer permitted unless you are deliberately evoking old use:
If I had a hammer ... ⇨ ∗Had I a hammer ...
Inverted had, were and could are understood as irrealis (unreal) or counterfactual in mode. Should, however, has realis, indicative (albeit tentative) significance, just as it does in uninverted position:
If I go to town I will bring you back a present.
If I should go to town I will bring you back a present.
Should I go to town I will bring you back a present.
All of these inverted constructions are markedly formal. They are rarely encountered in conversation, and they are never obligatory. You may omit them entirely from your speech and writing, in all registers, and they will never be missed.
Putting the condition first, as in the example you provided, serves to place more emphasis on the condition than the independent clause, which may be important for the overall impression you're trying to make. I think it is mainly a matter of style whether you choose to do this or not. Within the greater context of the piece you're writing, inverting conditional sentences like this can also serve to break up the pattern of repeatedly using the un-inverted (I would..., had I) form.
Your example is of an unreal past condition (third conditional):
If I had continued ... ---- Had I continued ...
Inversions like this might occur in formal or literary styles, with unreal conditionals. You can see examples on p. 457 of The Teacher's Grammar of English with Answers: A Course Book and Reference Guide and on p. 9 of Inversion Written and Spoken Contemporary English. You can omit "if" and then invert the subject and "had" or "were". Third conditional sentences can always be inverted because the auxiliary "had" can be placed at the beginning. The inversion in the second conditional is also possible but there are two cases:
1) when the verb in the if-clause if "to be". Then we invert the verb and subject:
Were I in your place, I would do exactly as you have done. (Were I --- If I were)
2) when there is a different verb. Then the inversion is not possible. We can use "was/were ... to ...":
Were I to live another 10 years, I would be 95. (Were I to live --- If I lived)
You can also omit "if" both with real and unreal conditionals if you use "should", but this is a different case, there is no inversion of the verb and subject.
