Mirar means 'look at' so no further prepositions are required.
So "¡Mira la frontera!" (tú)
'Mire la frontera!" (usted)

Just another question for someone, am I right in thinking that people sometimes say ¡Mirar la frontera! instead of 'Mirad la frontera' (vosotros)

By the way frontera is a border in the sense of 'frontier' (as your other items are household items) I'm not sure what the border of a room is called. 'borde''

tad said:

By the way frontera is a border in the sense of 'frontier' (as your other items are household items) I'm not sure what the border of a room is called. 'borde'?

Hi tad
I was born in London, in the East End. Never heard the phrase "border of a room". We just called it the walls, las paredes, jeje

tad, what is this, a new avatar every day?

Dale, what DO you mean by the border of a room? A wallpaper border or what?

I'm thinking of orilla or parte externa, but not sure . . .

Ha, well I mean "border" as in, for example the border dividing two countries.

For example, the Canadian-American border.

If you mean "look at" in the literal sense of using your eyes to perceive something, it would be mira, but if you mean it in the sense of thinking about something as an example ("Look at Herbert Hoover"), then it would be something else. I have a hard time imagining a situation where I would need to say "Mira la frontera."

As for using the infinitive mirar for a command, yes, it can be done, but that is usually a formal way of saying something, such as on a sign: No fumar.

Eddy said:

tad said:

By the way frontera is a border in the sense of 'frontier' (as your other items are household items) I'm not sure what the border of a room is called. 'borde'?

Hi tad

I was born in London, in the East End. Never heard the phrase "border of a room". We just called it the walls, las paredes, jeje

We would say the walls in North London too.
West Ham or Leyton Orient Eddie'

Natasha said:

tad, what is this, a new avatar every day? .

I change it every Sunday....like my underpants.

...not as often as Heidita it would seem.

tad said:

I change it every Sunday....like my underpants.
Well if Heidita started a thread about the frequency with which she changes her underwear, the moderators were quite right to have deleted it.

Her avatar, Samdie, her avatar. I deny any knowledge of Heidita's underwear usage!

tad said:

Eddy said:

tad said:

By the way frontera is a border in the sense of 'frontier' (as your other items are household items) I'm not sure what the border of a room is called. 'borde'?

Hi tad

I was born in London, in the East End. Never heard the phrase "border of a room". We just called it the walls, las paredes, jeje

We would say the walls in North London too.

West Ham or Leyton Orient Eddie?

Unfortunately neither. It was Charlton, the other side of the river. Had to follow my father's team.

tad said:

Her avatar, Samdie, her avatar. I deny any knowledge of Heidita's underwear usage!

In that case, I would suggest "I change it (like my underpants) every Sunday ... not as often as Heidita it would seem." Still some ambiguity but less, I'd say. jeje