GRE Text Completion: Fundamental 24 Sets-GRE填空基础24套 - 6K26465JWA203100!

Bubble gum is not a topic usually treated seriously, so it is appropriate that this new book tracing the cultured history bubble gum has a ____________ tone. A. morbid B. didactic C. pedantic D. flippant E. facetious F. reticent