i want find a given pattern in a paragraph in java Strings?

Here is my problem description,

String str="We may use the name you provide for your Google Profile across all of the services we offer that require a Google Account. In addition, we may replace past names associated with your Google Account so that you are represented consistently across all our services. If other users already have your email, or other information";

Now String pat="we offer";

so i need to find the pattern 'pat' in the string 'str' and also i need the words starts with same pattern ...like " we may","with your",...etc.

please help me...!