In any case, to wear an improper expression on your face (to look incredulous when a victory was announced, for example) was itself a punishable offence. There was even a word for it in Newspeak: FACECRIME, it was called.
hope that i helped :)
Answer:
Common suffixes and examples
Noun suffixes
suffix
examples of nouns
-age
baggage, village, postage
-al
arrival, burial, deferral
-ance/-ence
reliance, defence, insistence
-dom
boredom, freedom, kingdom
-ee
employee, payee, trainee
-er/-or
driver, writer, director
Your answer would be "seeing is believing." The scientist was only telling the character about what the time traveling machine could do, but needed to actually show the character that the machine wasn't a fraud by actually sending it through time.