reCAPTCHA...even if people do not write the code, i still get the email forms.

Hi there,Need some help.I installed reCAPTCHA in the form as mentioned the instrucction of PHP. but i still get the emails that are not filled with the reCaptcha codes. but i do get answe if they do not fill the form...but doesnt help if that is the case i still received those form message. When you type correctly there is also the right answer...I would like to know how people must fill the code before submiting the code.or if the submit and the code is not filled i dont get the message. Hope you can read my questions...thanks to all of you.