the secret of nature, they young scientist has little time for entertainment.
Don’t you think it ____ surprise that ____ German can’t speak ___ German language?
He made another wonderful discovery, ____ of great importance to science.
-- _____! I’m practising my writing while you must bother me !
People in developed countries are supposed ____ more healthy food before than what they have today.
The engine of the ship was out of order and the bad weather _____ the helplessness of the crew at sea.