Dynamically adding HTML form field using jQuery

Since I cant use div inside forms, I wonder how can I add new field in the middle of the form (and I can't use .append() here) without reloading the page or rewriting the form? (using jQuery)

EDIT: this is the HTML:

<form id="form-0" name="0">
<b>what is bla?</b><br>
<input type="radio" name="answerN" value="0"> aaa <br>
<input type="radio" name="answerN" value="1"> bbb <br>
<input type="radio" name="answerN" value="2"> ccc <br>
<input type="radio" name="answerN" value="3"> ddd <br>
//This is where I want to dynamically add the new radio or text line

<input type="submit" value="Submit your answer">
//but HERE is where .append() will put it!

</form>