下列句子中,划线的成语使用不恰当的是( )
— Four students in Qingdao stood in line against a man to save a woman teacher at the school gate.
— _________ great courage they had!
“国以民为本,民以衣食为本,衣食以农桑为本”这句话是谁说的?( )
The findings support another study which showed that being happy ______ reduce the risk of heart disease.
人受惊吓时,体内某物质在血液中的浓度比正常时要高,这种物质最可能是( )