完形填空

　　As the first report of the accident came in, Burton was sitting in his office on the top floor of the building．　　1　　, realizing the seriousness of the whole incident, he moved to a ground floor room with a small waiting-room to look 　　2　　 the matter himself, leaving his second-in-command to take over all the other 　　3　　．

　　He 　　4　　 the first witness almost at once, making sure that everything that could be done to put him at 　　5　　．However, the witness was obviously nervous and Burton took great pains to 　　6　　 what he said thoroughly, choosing and checking each word 　　7　　 and taking the man's statements down himself．The witness had called the 　　8　　 and he'd waited until the ambulances began to arrive, then 　　9　　 the first police car arrived on the scene, he'd been asked to 　　10　　 to the station which was what he had done．Burton 　　11　　 that regrettably it would be necessary for him to go to court because of the serious nature of the 　　12　　．More he couldn't say at present．He'd be 　　13　　 if the man could keep in touch with the police．

　　When he had 　　14　　, Burton put his head in his hands and considered before 　　15　　 for the next witness．The man couldn't be 　　16　　 as a hundred percent witness because he had been behind a wall when the explosion 　　17　　．But in spite of his nerves, Burton had the impression that he was 　　18　　, not afraid of relating himself to it and a fairly exact observer．

　　Well, there would be 　　19　　 descriptions and no doubt all these would be put into place and the whole picture would become clear．He 　　20　　 his head and pressed the bell on his desk．“Next witness please,” he said．