I don't have a partner to practice English with.为什么with要放在后面

to practice English with.是
,修饰 a partner同时to practice English with与a partner又构成
.即practice English with a partner,因此with不能省略又如：I have no seat to sit in .我没有座位坐.They have nothing to worry about.他们没有什么忧虑的.