Can I say in this way - ‘Can they not be on speaking terms so far?’ Or it is not correct? How would you say the same?
The problem is that I need to tell it with usage of a verb ‘can’ because I learn a new grammar on this topic.
I don’t understand your sentence. You cannot force sentence patterns in such a way. You need to consider a different sentence which can use the word ‘can’ in a more natural way.
Can they not see the results for themselves?
Can they not understand our problem?
There is a Russian sentence in my textbook which I need to translate into English using a verb ‘can’. I’ll try to explain a meaning of the sentence. For example, you know that Tom and Becky didn’t speak to each other. You meet your common friend Ben who tells you something and accidentally says that Tom doesn’t want to invite Becky to some party. Аnd ask him if Tom and Becky still not speak? You try to express a feeling of surprise.
I’ll write this grammar here:
Study the use of ‘can (could)’ in the meaning of surprise, strong doubt, disbelief in interrogative and negative sentences.
Can he be a coward?
Can (could) be unfamiliar with this artist?
She can’t (couldn’t) be more than twenty.
He can’t (couldn’t) have missed such a chance.
I thought that there is no Russian people who know both Russian and English well. But I can write - Неужели они всё еще в ссоре (не разговаривают)?