OK.

Materials specs

battery 12 volts 12 ah (as usual )
fuse (12 volt/1 ampere (let's say))
bulb (12 volt/5w )

Ok, the line 1 joined the terminal - and + causes it to short-circuit. but it's have own fuse to protect itself. so, it will not affect the line 2?

as you may notice, both line have their own connection. they are directly put on the battery.

um,what's your comment? am i correct? i hope so.

 

It takes time (maybe 1 second or two seconds because the battery is not very powerful) for the fuse to heat up then burn out. During this time the the battery is shorted by line 1 and the light bulb will be very dim.

 

It takes time (maybe 1 second or two seconds because the battery is not very powerful) for the fuse to heat up then burn out. During this time the the battery is shorted by line 1 and the light bulb will be very dim.

But after one or two seconds, the light brightness will back to normal?

 

But after one or two seconds, the light brightness will back to normal?

I guessed one or two seconds because I don't know your battery and I don't know your fuse. The fuse might burn out in 10 seconds.
When the fuse burns out then the battery returns to normal with only a small anount of its charge gone.