【单选题】TEXT A Saying“thank you”is probably the first thing most of us learn to do in a foreign language. After all,we’re brought up to be polite,and it is important to make a good impression upon other peopl...
A.
people are unconcerned about politeness nowadays.
B.
“thank you”remains the best expression of gratitude.
C.
there is a variety of expressions of appreciation.
D.
there are more formal expressions than informal ones.