focus 名词时后面介词不能用for，只能用on，因为focus on为固定搭配，中文意思是“专注于，集中于” 他说他突然关注外交政策并不是受总统政治的驱使。He said his sudden focus on foreign policy was not motivated by presidential politics...
concentration 英音: ['kɔnsen'treiʃən] 美音: [,kɑnsɛn'treʃən] 名词 1.[C,U]集中 2.不可数名词：专心，专注 3.不可数名词：浓缩；浓度 ihvhhcrease in density the spatial property of being crowded together complete attention; intenhse mental effort...