A good voice is pleasant to listen to because it communicates a positive message.Keep in mind the following qualities of a good voice：
Speak in a voice neither too loud nor too soft.Speak louder when giving important information.
Speak slowly enough so that the listener has a chance to understand your message without your having to repeat it.Keep in mind that as you speak the other person may be taking notes.
Pronunciation is the correct way to say a word.To avoid mispronouncing(读错音)words，you may wish to check the pronunciation of unfamiliar words in the dictionary before you use them.
People with an accent unlike yours may not understand your pronunciation of some words.You also may not understand the pronunciation of some of their words.In these cases, careful pronunciation is very important for effective communication. You may need to repeat or spell words that are unusual or easy to be misunderstood.
21.When speaking on the phone, the essential factor for successful communication is your _ _ _ _ _ _ _ .
A.voice
B.gesture
C.eye contact
D.facial expression
22.To give important information，a person speaking on the phone should _ _ _ _ _ _ _ .
A.keep a pleasant manner
B.use familiar words
C.lower the voice
D.speak louder
23.The speaker is advised to speak slowly in order to help the listener to _ _ _ _ _ _ _ .
A.remember some words
B.repeat the information
C.check the message
D.take some notes
24.To avoid mispronouncing unfamiliar words，you are advised to _ _ _ _ _ _ _ .
A.check them in a dictionary
B.pronounce them loudly
C.use other words instead
D.ask others for help
25. Speakers sometimes need to spell some words to help listeners to understand _ _ _ _ _ _ _ .
A.long sentences
B.unusual words
C.difficult questions
D.important expressions