[Grammar] Is "...suggested he knock/knocking" correct ?

[alexbrasile]

Ladies and Gentlemen !!!!

I am studying for CAE and in one book I got this in the Answer key. On this site, I have seen someone else saying that the correct would be : "...suggested that he knocked"
So, is "...suggested he knock/knocking" wrong ?

Thank you for helping me

 

[Raymott]

Ladies and Gentlemen !!!!

I am studying for CAE and in one book I got this in the Answer key. On this site, I have seen someone else saying that the correct would be : "...suggested that he knocked"
So, is "...suggested he knock/knocking" wrong ?

Thank you for helping me

You really should write a sentence. It's often impossible to tell whether a three-word phrases is "wrong" or not without seeing how you want to use it.
However, I can't think of a use for "suggested he knocking" in any context.