Once a year, for what now seems like many years, I report to school. The occasion is something called "curriculum night," and the school is my son's. For an hour and a half or so, I duplicate his day -- go from class to class to hear his teachers explain the curriculum. Once a year I have done this, and once a year, on this night, my heart freezes in my chest. I am once again a student.

Recently, it was chemistry that brought back the old feeling. The teacher seemed wonderful, but as she talked, my attention drifted to the syllabus, and there I saw all the old words: atomic structure, chemical bonding, ionic, covalent, periodic table. And on the wall was the periodic table itself, a map of the complex and the incomprehensible, a maze of letters and numbers in which everything in the world -- everything we are -- is represented by a symbol.

Richard Cohen. Please stand and tell the class the symbol for strontium. Please define a valence and, just for good measure, a covalence. Who is Avogadro, and what is his law? Richard Cohen, please come to the board and work out a problem. Make a fool of yourself. Embarrass yourself before your friends. Turn your back on the class, let them giggle and make faces. Richard Cohen, you who are lost, who understand almost nothing about chemistry, who have learned little and will forget even that in the panic of the moment, come to the board so that you may sweat and redden and wonder how you look from the back.

Next, I go to geometry. I was somewhat better at that than at chemistry, but I never really understood it. Here, again, the teacher outlines the curriculum, and this time a parent raises his hand. He was checking his daughter's homework the other night (he checks her geometry homework!) and found that although she got the answer right, she didn't know why. With that, the man describes the problem and then recites how it should be solved. I find myself nodding as if I know what he is talking about -- bluffing, as I used to -- nodding to him, to the teacher, faking it. He might as well be speaking Urdu. Hypotenuse. Sure. Isosceles. Absolutely. The square of the circle is the angle of the sine over the hypotenuse. I couldn't have said it better myself.

It has been this way since the beginning, since I first went to curriculum night. Back then, the desks were smaller, the courses elementary and comprehensible, but it hardly mattered. I became a student. I sat in the back of the room, as if afraid of being called on. My attention drifted. The teacher talked, but I read posters on the wall or looked out the window. Periodically, I tuned in -- smiled, nodded -- tried to refocus but drifted off again. Something still tugged me from the room.

When I was a student, I believed in the conspiracy theory of parenthood. I thought all parents had gotten together to lie about school, to say it was the best time of their lives. They would pretend envy at Christmas and Easter vacations, a 9-to-3 day and two months off in the summer. They would depict life after school (real life) as being infinitely tougher -- a vocational treadmill, a chore in which the rewards were what little money they could make. School, they said, would be the happiest time of my life. What were these people talking about?

As adults, we structure our lives to avoid precisely the sort of pain school routinely inflicted. Only politicians and athletes, who either win or lose, still pass or fail. Most of us never get called to the board. Most of us learn to avoid situations in which we cannot cope, to master something and never to do what we know we cannot do. There is no periodic table in the lives of most of us. Who takes exams? Look, just for example, at how teachers -- of all people -- fight the concept of competency testing.

Only once in my professional career did I feel as I did in school. I had to write a story about the District of Columbia's budget -- a periodic table written by bureaucrats. There had been no briefing. No explanation. I read the budget and wrote my story. Somehow, I could not account for millions of dollars -- whole sewer systems, roads, buildings. I wrote and rewrote, but fatigue set in. The numbers proved elusive -- a kind of arithmetical Holy Grail, first here, then there, always moving away from me. That old feeling, the claustrophobia, the warmth then chill, overwhelmed me. I was being called to the board, only the class behind me had been replaced by fellow reporters, editors and newspaper readers. Finally, a colleague helped me. That was my last budget story.

In Spanish this year, the teacher mentioned the subjunctive. Oh, how I remember the subjunctive or, more precisely, how I could not remember the subjunctive. I hardly know what it is in English. The subjunctive was my ruination, the mood of the verb in which Spanish turned into a tepid aspic of conjugations that oozed off my plate. The word brought back all those old feelings of insufficiency, of drowning in a brew of tenses -- the conditional, the future, the pluperfect. God, what's the pluperfect?

Once a year, I duplicate my son's schedule, but not -- because he is a better student than I ever was -- his experience. Then, like most parents, I return to the world I have mastered. Here there are no periodic tables, there is no subjunctive -- no getting called to the board. Once a year, I learn the curriculum, and once a year, too, I am reminded of what it's like to be a student. Once a year is enough. ::