Frances Grant: That 'lost' feeling

One striking thing about television as a medium is its ability to make the most obvious things even clearer. For example, you didn't need genius IQ or even only a moderate serving of the grey matter to grasp the gist of last week's Expose documentary, a local offering about teen sex.

All power to the brave teens who fronted up and gave us the low-down on what is often difficult subject matter for people of far more mature years. Their articulate, frank contributions were appreciated.

It was the scripted commentary that - to employ a bit of teenspeak - sucked.

Who was it aimed at? Teens? In which case, they might well have asked of the earnest narrator, why are you speaking to us like we are a species of retarded jellyfish?

Perhaps it was supposed to be for their parents. Everyone knows that parents of teenagers can be strangely ignorant or just too plain frightened to contemplate what Britney, Brad et al might be getting up to after a few alcopops in the pool room.

But surely even the dimmest guardian doesn't need to be told that "being a teen is about change - sex is one of those changes", or would be surprised by this conclusion: "Teenagers and sexuality seem firmly locked together!"

Later on we learned that teenagers were "not as mature mentally or emotionally as physically". Astounding stuff. Between these breathless proclamations of the startlingly obvious, the teens themselves were a treat, enlightening us, for example, on one of the more embarrassing side-effects of having a strong Christian faith: "Obviously God is watching me. I don't like Him watching me having sex, of course." And another gem, on the appropriate age to lose virginity: "Hopefully you have had sex before you are 56 or something, otherwise it's just wrong."

In the meantime, some potentially interesting questions got lost, such as what is an entire generation of girls who think a skirt the size of a belt and not much on top is normal street wear going to get decked out in if, for a change, they decide to don something provocative?

Telly is a contradictory beast. An equally striking feature is its ability to be wilfully obscure, at least where the David Lynch school of telly drama is concerned.

I can't quite seem to give up on Lost, even though its perpetual tease is about as sophisticated as a 14-year-old mall rat in the above-mentioned micro-miniskirt and nano-top.

It's enough to make you wish the huge, ravenous polar bear that stalks the tropical island will get every last one of the stranded plane-crash survivors. All have had their back-story and now we seem to have progressed to a second round of back-story behind back-story. Or in Claire's case, a dose of amnesia, which means her whole story can simply start again.

Still you keep hanging in there, hoping, like the discoverers of the shape of the human DNA molecule, to get some insight as to what the structure actually is.

Perhaps like the castaway Frenchwoman's recorded message, the story is stuck on an endless loop which will run around and around after its own tail for 16 years. Perhaps the title Lost applies to the viewers as much as the characters and, like God watching teen sex, the show's creator is secretly looking down on us and having a good laugh.

Perhaps the survivors have been pulled into a parallel universe even further beyond help or rescue than anyone in New Zealand who calls 111. Hopefully we'll get some satisfaction before the youngest cast member, the boy Walt, is 56, or something. Otherwise it would just be wrong.