left realising vs. realised

[Xianyu]

David Cameron, UK prime minister, went to China leading a coalition government and a large delegation of British business figures, hoping to do business. He [color=red]left realising that achieving big export deals with China is a slow and difficult process, even though he spoke softly on human rights and avoided gaffes.

Hi, everybody!
Can ‘realised’ substitute for the part in red without changing its meanings?

Thanks a million!

Xianyu

[Beeesneees]

‘realised’ would be grammatically incorrect. ‘He realised that…’ would be okay, but you would not be able to use ‘left’ with it, so there would be no indication of when this realisation occurred.

[Xianyu]

@Beeesneees

‘realised’ would be grammatically incorrect. ‘He realised that…’ would be okay, but you would not be able to use ‘left’ with it, so there would be no indication of when this realisation occurred.

He left [color=red]realising that achieving big export deals with China is a slow and difficult process, even though he spoke softly on human rights and avoided gaffes.

Thank you so much, Beeesneees.
Can I think that the clause with the present participle functions as an adverbial modifier, which modifies ‘left’?