Thereistheappreciationofthesalienthistoricaltruth________theagingofadvancedsocietieshasbeenasuddenchange
句子写作：Thepianoplayerbegantosingloudly.
Yourbikeneeds_____.You‘dbetterdoirightnow.
“Itwasverycoldtesterday.”
“_____.”
InCanadathefederalgovernmentshavealwaysbeenformedby________.
