【单选题】

As it came near the corner, the taxi stopped suddenly. The driver got out looking very 21 .

A、big lorry which had been 22 the taxi stopped too. The taxi driver was now standing at the corner looking up at the sky 23 the lorry driver went to 24 him.
A、number of cars behind were 25 to stop as well and soon a large crowd of people 26 gathered at the corner　　The 27 of all this trouble was a very strange 28 . It sounded as if thousands and thousands of 29 were singing together. The noise was quite 30 and many people looked disturbeD、The most extraordinary thing was that, apart from one or two pigeons, 31 was not a bird in sight. No one was able to solve the mystery 32 two policemen arriveD、They noticed a large advertisement 33 a film high up on a wall nearby. 34 the noise seemed to be coming 35 this direction, they climbed up and found that a tape-recorder had been hidden 36 the advertisement. The noise made by birds singing was being broadcast over powerful loudspeakers so as to 37 the attention of passers-by. The police asked the 38 to take the recorder away because the advertisement had attracted 39 much attention that it was 40 for a great many cars and buses to move freely in the street.
A、in
B．to
C．into
D．from