Everywhere he goes,he sends himself a postcard
此句应该是错的
因为Everywhere he goes 是个地点状语从句,everywhere 不能作从属连词,不能引导状语从句
正确说法是：
Wherever he goes,he will send himself a postcard.
= No matter where he goes,he will send himself a postcard
everywhere,wherever的区别,两者位于句首时.