disappearing Dinosaurs 灭绝的恐龙.这里为何disappear 是—ing形式的啊?不是已经结束的

The old-fashioned general store is fast disappearing. This is, perhaps, a pity, because shopping today seems to lack that personal contact which existed when the shopkeeper knew all his regular customers personally. He could, for instance, remember which brand of tea Mrs. Smith usually bought or what sort of washing-powder Mrs. Jones preferred. Not only was the shop a center of buying and selling, but also a social meeting place.
A prosperous general store might have employed four or five assistants, and so there were very few problems in management as far as the staff were concerned. But now that the supermarket has replaced the general store, the job of the manager has changed completely. The modern supermarket manager has to cope with a staff of as many as a hundred, apart from all the other everyday problems of running a large business.
Every morning the manager must, like the commander of an army division, carry out an inspection of his store to make sure that everything is ready for the business of the day. He must see that everything is running smoothly. He will have to give advice and make decisions as problems arise, and he must know how to get his huge staff to work efficiently with their respective responsibilities. No matter what he has to do throughout the day, however, the supermarket manager must be ready for any emergency that may arise. They say in the trade that you are not really an experienced supermarket manager until you have dealt with a flood, a fire, a birth and a death in your store. (Note: Answer the questions or complete the statements in NO MORE THAN TEN WORDS.)
小题1: Why is it a pity that there are fewer old-fashioned general stores now? _____________________________.
小题2: The shopkeeper was often the most well-informed person in the neighborhood because _____________________________.
小题3: The words “… a flood, a fire, a birth and a death …” in the last sentence refer to _____________________________.
小题4: What must the manager do every morning? ___________________________.

With more and more forests disappearing, today the public is much concerned about the way _________.

A．nature is being ruined	B．which nature is ruined
C．on which to ruin nature	D．of nature to be ruined

Many beautiful fish are disappearing____ the severe(严重的) pollution.

A．because of

B．because

C．so

D．thanks of