Hi I strive to avoid passive voice to make my writing more vivid, there is a sentence where I have to write
He is based in Australia
Other than saying
He bases in Australia
Is there any other better suggestion ? Thanks
First and foremost, Strunk&White's "rule" that passive constructions should be avoided is not a rule. It is a general style advice, and actually its validity is very debatable to say the least.
Then about your sentence. There is nothing wrong with he is based. It is natural, easy to understand and idiomatic. Changing the sentence in an attempt to avoid what you perceive as a passive construction is likely to create an unfamiliar, more difficult to read sentence that is unlikely to make your writing more vivid. Quirky yes, but that is not the same thing.
Wait, did I say perceive as passive? Yes indeed. He is based can arguably be seen as an active construction! If I describe someone as strong, the sentence he is strong is not a passive construction at all. Strong modifies he, and is simply is a copula.
Of course, but strong is an adjective... but past participles of verbs can also be used attributively, in similar ways we use adjectives.
In the sentence he is based in Australia, I see a description of a situation, not a description of an action that was performed. In a passive sentence, I expect an implicit or explicit actor that performed the action:
The dog was beaten (by someone!).
In the case of
He is based in Australia.
There is not any part of my mind that starts wondering who bases him in Australia. The sentence just tells me his location, describing a situation, rather then describing an action. So based in Australia is an attributive phrase that modifies he, with is again as a simple copula.
No passive construction, so no need to change anything, even if you want to follow Strunk & White (which is probably something that should only be done with caution and moderation anyway!)
"Use the active voice" is a typical section head. And the section in question opens with an attempt to discredit passive clauses that is either grammatically misguided or disingenuous.
Sadly, writing tutors tend to ignore this moderation, and simply red-circle everything that looks like a passive, just as Microsoft Word's grammar checker underlines every passive in wavy green to signal that you should try to get rid of it. That overinterpretation is part of the damage that Strunk and White have unintentionally done.
What concerns me is that the bias against the passive is being retailed by a pair of authors so grammatically clueless that they don't know what is a passive construction and what isn't. Of the four pairs of examples offered to show readers what to avoid and how to correct it, a staggering three out of the four are mistaken diagnoses.
I think you're taking things a bit too far by supposing that switching He is based in Australia to "active voice" will somehow make your writing "more vivid".
In principle you could make he the subject of the verb. But it would need a reflexive construction...
He bases himself in Australia
...and it's probably not appropriate anyway. The original is ambiguous about whether he or his employers are the ones who decide where to base him, but usually it would be the latter...
His employers base him in Australia
...or more likely...
His employers have based him in Australia
Regardless of whether you substitute some other subject (the company, his boss, or whatever), you've unavoidably introduced a pointlessly-distracting "agent" you probably didn't want. I assume the reason for making the statement in the first place is to draw attention to the fact that Australia is where he's based (not somewhere else).
By explicitly referencing whoever caused him to be based there, you're just undermining the original intent of the statement (Where is he?) and diverting attention to Who put him there, and why?
TL;DR: There's a case for saying excessive use of passive voice can be undesirable, but this doesn't imply you should always avoid it. In this case it's probably best to leave well alone.
He is based in Australia.
is in neither active nor passive voice.
But because forms of to be are commonly used in passive constructions, some people have mistakenly conflated the two. If you are dealing with an editor or teacher who feels this way or you truly need a different phrasing, maybe
He works from Australia.
His base of operations is in Australia.
would meet your needs.
Either way, the sentence *He bases in Australia. is ungrammatical and should be avoided.