Can you really use 是 in this sentence? I've only ever heard it with 有!
Yes, you can.
Is there any difference between 这个句子 and 这句话？
I'm also wondering the difference, as it does not accept 句子.
Edit: sorry, yes it does I just forgot to put 是. (face palm)
I cannot reply correctly with the words offered. there is a character missing
这个句子意思什么 - any particular reason this structure would be incorrect?
It has to be 什么意思, that is just a set structure. Other way round does not work
You can't use that structure because 意思 is a noun not a verb.
Will be correct if it is '这个句子的意思是什么?'
The word ge was not among the choices to complete the sentence
"what does this sentence mean"
There is an error in the words in Chinese that are offered to choose from.
There should be a she ge (but instead, there is a a she ju)... not the fault of the person trying to reply