单项选择题
A.They cannot pronounce/n/
B.Interlangue interference because there is notthe sound /n/in their mother tongue
C.The teachers do not have a good teaching method
D.They do not like to pronounce nasal sounds
单项选择题 （）produce fast and fluent speech with good intonation and pronunciation but the content of their speech ranges from mildly inappropriate to complete nonsense,often as unintelligible.
单项选择题 A linguist regards the changes in language and language use as（）.
单项选择题 The discovery of Indo-European language family began with the work of the British scholar（）.