Database Software

Hi all,
I'm using Oracle text to execute a full text search. I indexed my column like that

CREATE INDEX cm_property_text ON cm_property(text_value) INDEXTYPES IS CTXSYS.CONTEXT

After that, I inserted into the field text_value one line have contain is: "I and you or other" and then execute the command to synchronous my Index:

Begin
CTXSYS.CTX_DLL.SYNC_INDEX('cm_property_text');
end;

Then I execute the Query to select out the row have text_value contains text value is "I and you"

SELECT * FROM cm_property WHERE CONTAINS(text_value,'I /and you')

But I didn't receive anything. And I tried change to the text input search like that

SELECT * FROM cm_property WHERE CONTAINS(text_value,'I /and you /or other');

And I had one row which is the row I inserted before.

I really don't why? Who can help me to explain about it?

Thank you so much!