if you dont supply cascade it wont drop.

Code:
SQL*Plus: Release 9.2.0.4.0 - Production on Thu Sep 16 09:57:45 2004

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.


Connected to:
Oracle9i Enterprise Edition Release 9.2.0.4.0 - 64bit Production
With the Partitioning option
JServer Release 9.2.0.4.0 - Production

SQL> grant connect, resource to dave identified by dave;

Grant succeeded.

SQL> connect dave/dave
Connected.
SQL> create table test (num number);

Table created.

SQL> 
SQL> 
SQL> connect / as sysdba
Connected.
SQL> drop user dave;
drop user dave
*
ERROR at line 1:
ORA-01922: CASCADE must be specified to drop 'DAVE'


SQL>