1) Can you commit a force die to keep the result of sensing living beings within the range?

2) What does this mean for the Basic Power - "The user may not activate this multiple times." The effect cannot be repeated in an encounter? Or the effect can be activated only once per round?

You don't commit force dice for that effect.

It means you can't just keep activating to read more and more target's thoughts.

It means you can activate it against or for one attack during the round unless they have the upgrade to use it twice.

Not reading thoughts , but sensing living beings within the range, but I understand it is also not allowed. Thx!

NP, enjoy.

I have asked the wrong way.

How long does the effect of sensing living beings lasts? Up to the GM? I tried to search for a clarification, but with no luck.

It depends, narratively or in structured play? Narratively it's a GM's call, in structured play I'd make them roll every round since it is specifically not called out as a commit Force die option. If they're trying to use it like some kind of Force radar narratively to spot the aliens in the vent ducts then I'd call for more than one roll, or start billing Strain or something. The gray box points out it should assist PCs, not do the work for them.

I say one Action to commit both Force Dice. Yes it takes an Action to activate the power, but never to commit Force Die. Otherwise all those Force Talents that ask for commitment of Force Die to activate would require an additional Action to use along with the Action they may relate to.

Nah, I wouldn't be that harsh. Technically you can leave them up and there is some guidance on Strain recovery. The defensive and offensive Talents, Force ones included, are at most Maneuvers, many are Incidentals.

For an accurate reflection of the star wars movies I suggest you allow your force users to default to keeping sense (attack/defense) powers active, unless they specifically uncommit the dice to do something else. It's pretty clear that in the movies both attack and defense powers are active at nearly all times. An action reflects aproximately 1 minute of what a character is doing. To suggest that it takes an action or worse two actions to activate sense would be akin to watching dragon ball z instead of star wars.

It is pretty clear in the movies the combat levels of sense are always up but MOST jedi have to have sense active to detect things. Somethings are so powerful even jedi without active sense powers will notice though (destruction of a planet).

Reviewing the book it is narritive whether you decide to penalize players for keeping up defensive moves I would suggest you do not, but extended use of the move power definately seems like a strain candidate.