well-known to us all that knowledgeis __ treasure, but practice is ___ key to it

Mr Black is __________ father

How was _______dinner at Mike’s house –It was great. Mike’s mum is ________wonderful cook.

______ that the Belt and Road Initiative will benefit China’s economy, we are optimistic ____ the future of the country.

Tyron was very angry, but coolheaded enough to________rushing into the boss’s office. [ ]