I'm a beginner in Chinese and I'd like to ask you something about these sentences below :
What does 是 in those sentences mean/indicate? I've tried to look for the explanation of why 是 is placed before 因为 but I couldn't find anything except this structure : "之所以...是因为". But still, I don't think that the "之所以...是因为" structure is the one being used here.
The others are :
For this one, I'm quite sure 是…的 here is that one 是…的 structure which is used to emphasize (like time, place, or manner). But the thing is, I don't know whether or not the 是…的 structure can be used to emphasize something like 没有 or 要.
Could you please explain to me? Thank you in advance.