When a group of children politely stop a conversation with you, saying: "We have to go to work now," you're left feeling surprised and certainly uneasy. After all, this is the 1990s and the idea of children working is just unthinkable. That is, until you are told that they are all pupils of stage schools, and that the "work" they go off to is to go on the stage in a theatre. Stage schools often act as agencies to supply children for stage and television work. More worthy of the name "stage school" are those few places where children attend full time, with a training for the theatre and a general education. A visit to such schools will leave you in no doubt that the children enjoy themselves. After all, what lively children wouldn't settle for spending only half the day doing ordinary school work, and acting, singing or dancing their way through the other half of the day? Then of course there are times for the children to make a name and make a little money in some big shows. Some stage schools give their children too much professional work at such a young age. But the law is very tight on the amount they can do. Those under 13 are limited to 40 days in the year; those over 13 to 80 days. The schools themselves admit that not all children will be successful in the profession for which they are being trained. So what happens to those who don't make it? While all the leading schools say they place great importance on children getting good study results, the facts seem to suggest this is not always the case. Professional work as used in the text means   _  .
ordinary school work money-making performances stage training at school acting, singing or dancing after class