听力原文： Strikes are very common in Britain. They are extremely harmful to its industries. In fact, there are other countries in Western Europe that lose more working days through strikes every year than Britain. The trouble with the strikes in Britain is that they occur in essential industries. There are over 495 unions in Britain. Some unions are very small. Over 20 have more than 100,000 members. Unions do not exist only to demand higher wages. They also educate their members. They provide benefits for the sick and try to improve working conditions. Trade unioners say that we must thank the unions for the great improvement in working conditions in the last hundred years. It is now against the law for union members to go on strike without the support of their union. This kind of strike is called the unofficial strike and was common until recently. Employers feel that unofficial strikes were most harmful because they would not be predicted. However, these unofficial strikes still occur from time to time and some unions have also refused to cooperate with the law. As a result, the general picture of the relations between workers and employers in Britain has gone from bad to worse. (30)