how to find continuous absent days

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SQL-Server-2005

SQL-Server

i have problem to write stored procedure that find the continuous absent days
chektime column shows the user is present
table are as

CREATE TABLE [dbo].[CHECKINOUT](
    [USERID] [int] NOT NULL,
    [CHECKTIME] [datetime] NOT NULL,
    [CHECKTYPE] [nvarchar](1) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
    [VERIFYCODE] [int] NULL,
    [SENSORID] [nvarchar](5) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
    [WorkCode] [int] NULL,
    [sn] [nvarchar](20) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
 CONSTRAINT [aaaaaCHECKINOUT_PK] PRIMARY KEY NONCLUSTERED
(
    [USERID] ASC,
    [CHECKTIME] ASC
)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]

plz help me
thanks in advance