A、Less than 30 minutes. B、From 30 to 45 minutes. C、At least 45 minutes. D、More than 45 minutes. B短文提到，from 30 to 45 minutes，所以答案

To be successful in a job interview, you should demonstrate certain personal and professional qualities. You need to create a good image in the limited time available, usually from 30 to 45 minutes. You must make a positive impression which the interviewer will remember while he interviews other candidates. The following are some qualities you should especially pay attention to during an interview. [20]First of all, you should take care and appear to be properly dressed. The right clothes worn at the right time can win respect of the interviewer and his confidence in your judgment. It may not be true that clothes make the man. But the first and often last impression of you is determined by the clothes you wear. Secondly, you should pay close attention to your manner of speaking, since speech is a reflection of personality. You should reflect confidence by speaking in a clear voice, loud enough to be heard, without being aggressive or overpowering. You should be prepared to talk knowledgeably about the requirements of the position you are applying for. Finally, to be really impressive you must convey a sense of responsibility and enthusiasm for work. If you display these characteristics, with just a little luck, you’ll certainly succeed in the typical personnel interview.
19. How long does an interview usually last according to the speaker?
20. How can one give the interviewer a good first impression?
21. What should be the best manner of speaking for a job-seeker during an interview?