A．earnB．printC．tradeD．borrowNational forests make money……

单项选择题To solve the problem of dry mouths, one is advised to take cool milk.

单项选择题The first paragraph mentions three ways of activating the saliva in the mouth.

单项选择题The writer suggests that you go to see a doctor when you feel you are losing your voice.

单项选择题The writer’s advice about alcohol before you make a speech is to take one or two drinks so as to give yourself some confidence.

单项选择题Due to the effect of alcohol, your thought and your mouth will not coordinate properly.