why it only show the first question?

[analog robin]

Show your entire code, use a proper codeblock.
And fix that formatting. {Console.WriteLine("...");} is absolutely unreadable.

And to answer your question: I assume that your method runs into an error at the first Convert.ToInt32() call.
The methods of the Convert class are (largely) unnecessary. And they don't provide ways of error handling. So if the input you give them cannot be parsed to the target type, they'll just throw an exception. You should be able to see this behaviour if you execute your program through CMD instead of through your debugger.

[lofty locust]

which {console.writeline("...");}