Be overly

[Jignesh77]

One of the biggest mistakes students make in IELTS writing is to try and show off and be overly ambitious with their grammar
IELTS Writing- How to write complex sentences
What is the grammatical form,function and meaning of "be" here?
Thanks

 

[Barque]

It's a verb. It describes the state that they are in - a state of too much ambitiousness with their grammar.

Perhaps you should re-read some of your earlier threads on this word. Here are a couple:
To be
To be the best

 

[Jignesh77]

Is it a subjunctive use- plain be form or an imperative? Thanks for your help? Is "to" before "to try" is also applicable to " show off and be overly ambitious-in other words- to try and to show off and to be overly...?

 

[Barque]

I'm not too good with grammatical terms but it's not an imperative.

 

[Andygc]

It's the infinitive. Rewritten:
... writing is to try and show off and to be overly ambitious with their grammar ...