Tom had turned on/turned on...

[Banglardon]

What is the difference between the two following sentences?

1- I walked into the room. Tom turned on the light.

2- I walked into the room. Tom had turned on the light.

 

[Yankee]

What is the difference between the two following sentences?

1- I walked into the room. Tom turned on the light. At the moment you entered.

2- I walked into the room. Tom had turned on the light. The light was on before you entered.

Y.

 

[jutfrank]

Without any context, a simple difference in meaning is the sequence of actions. In one of those sentences, walking comes first and turning on comes second. In the other sentence, turning on happens first and walking happens after.

Can you see which sentence means what?


[Oops—cross-posted too late]