Now, most people have watches. As we know, Switzerland（瑞士） is famous for its watches. ___ , the watch was not _ in this country. It was the British who did. Many years ago, an Englishman traveled to Italy and on his way he went     a small town in Switzerland. This Englishman traveled in a carriage（马车） inside which there was a carriage watch. This was the __ kind of watch. A blacksmith’s（铁匠） assistant hoped to see the watch. He __ what it was. __ he asked the Englishman about it. “ It is a carriage watch,” said the Englishman. “ This machine can tell the ___ but now it isn’t working.”

At once the blacksmith’s assistant decided to try to __ it. So the traveler handed him the watch. He was very __. So it was not surprising that he was __ in showing it right. He even remembered how it was made. As soon as the traveler had gone, he made a watch of exactly the same kind.

So the watch-making was started in Switzerland. Today Swiss watches are sold all over the world.

暗埋管路连接应采用（）。

A．丝扣连接

B．压扣式管连接

C．水泥浇筑

D．焊接