模块编程里makefile的错误

到底我的makefile里什么地方写错了?

这是helloworld程序:
/*hello.c*/
#include <linux/kernel.h>
#include <linux/module.h>
#if CONFIG_MODVERSIONS==1
#define MODVERSIONS
#include <linux/modversions.h>
#endif

int init_module()
{
printk("hello world --this is the kernel speaking\n");
return 0;
}

void cleanup_module()
{
printk("short is the life of a kernel module\n");
}

这是makefile的内容:
CC=gcc
CFLAGS:= -Wall -DMODULE -D_KERNEL_ -DLINUX
hello.o : hello.c /usr/include/linux/version.h
$(CC) $(CFLAGS) -c hello.c
为什么我在xterm下一执行make就有这样的错误:
makefile:4: *** missing separator. Stop.

Makefile的格式！请执行info make，仔细阅读Introduction部分，Rule Introduction章节，尤其注意这句话：
A "command" is an action that `make' carries out. A rule may have
more than one command, each on its own line. *Please note:* you need
to put a tab character at the beginning of every command line! This is
an obscurity that catches the unwary.

检查这一行：
hello.o : hello.c /usr/include/linux/version.h