these have not had any effect这里为什么用these呢?能不能用this.these指的是J

these have not had any effect这里为什么用these呢?能不能用this.these指的是J These have not had any effect.effect 为什么不加s变复数呢? These have not had any effect. these have not had any effect but these has not had any effect but these have not had any effect 及句型.为什么中间有一个had these\this\have\those\ will the use of these products have any effect on the popula these是this的复数吗? DO you have any shoes these? these 能修饰不可数名词吗?this呢? these与this的音标