________ wise nation is one good at learning, especially ________ that is good at learning from difficulties.
The principle of the heating system in this building is that pipes ________ hot water from the boiler to every part of it.
People’s working efficiency usually decreases more or less when the temperature _________ 35℃ or even higher.
It is widely accepted reported in the western media that the drug ______ is now becoming a leading cause of teenager crimes.
“Boys and girls, you are asked to submit a(n) _______ of about 100 words of the lecture given by Professor Yu tomorrow” , said the teacher.
The windows _____, so you need not wash it again.