The question mark in URLs

I have been using VBA to access financial Tables on selected web pages, and have written a loop to allow the macro to go through each Worksheet in turn, but I get the message that the URL cannot be found - and it's because of that ? in the URL, which is an unacceptable symbol. How can this question mark be overcome .... I am using the sheet number and tab name as my looping variables. I am sure the answer is so simple, but I cannot find it ...any help, please?