[Grammar] I have never known him behave other than selfishly.

[jiaruchan]

I have never known him behave other than selfishly.----It is a sentence in an English-Chinese dictionary.

I want to know if it is grammatically correct to say 'know somebody behave'. Thank you

 

[Raymott]

I have never known him to behave other than selfishly.----It is a sentence in an English-Chinese dictionary.

I want to know if it is grammatically correct to say 'know somebody behave'. Thank you

I'm pretty sure that the 'to' is necessary. It is in AusE.

On the other hand, you can say:
I have never seen him behave other than selfishly.