Am I allowed to ask similar type of questions but not same questions frequently?
The challenge with these two questions is that they are missing key info. What class are you in? What book are you using? What is the definition of proposition from the class, notes, or book?
It might seem that there would be a single definition of "proposition" that everyone accepts, but that isn't so. For a brief intro, see Propositions in the Stanford Encyclopedia of Philosophy.
In mathematical logic, we move relatively quickly past the idea of natural-language propositions, after which we look only at formal languages in which there is a more objective definition of a "proposition" as a sentence in a formal language. The real interest in natural language propositions is in philosophical logic and in applications of logic to non-mathematical areas.
So natural "propositions" tend to be covered only in the very beginning of an introductory logic course. And, because they are natural language, it can be difficult to tell if they are intended to be propositions - this is where the emphasis provided by the definition in each course is important.
How can the questions be improved? First, read How to Ask a Good Question. Don't assume that the people on this site have access to your course materials. There are probably other examples that you have been given in the notes, book, or lecture - mention those in the question.
After you ask a question, as several commenters have mentioned, read and think about the answers and comments before asking a similar question. A follow up question is likely to be better received here if it shows that you have taken something from the previous answers and are now asking a more refined or specific question.