You can continue waiting, make inquiries or hire an immigration attorney.
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Consult with an immigration attorney directly. Tell him or her what you have filed to get the conversation started.
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Unfortunately you do not provide enough details on the type of application that you filed to know the average processing time right now. Many applications filed with the USCIS take longer than 5 months, so this could be normal. You should either make inquiries directly to the USCIS, or hire an attorney to make inquiries on your behalf, especially if the processing is "beyond normal."