expression前面加a还是an 瑞丽范 心理 2.06W 大中小设置文字大小 前面用an,例如:1、Well, now we have an expression for the energy.好,现在我们有能量的表达式。2、Its key is to find an expression for coefficient β.关键在于β系数表达式的求出。3、He screwed his face into an expression of mock pain.他面部扭曲,假装疼痛。 TAG标签:expression #