I don't have a partner to practice English with.请问此处为什么加with.?详细一点 ~谢谢~

I don't have a partner to practice English with.请问此处为什么加with.?详细一点 ~谢谢~
I don't have a partner to practice English with.请问此处为什么加with.?
详细一点 ~谢谢~

I don't have a partner to practice English with.请问此处为什么加with.?详细一点 ~谢谢~
定语从句,practice是不及物动词,加上with,才能接partner.