You will have a difficult time knowing who you best friends

应该是：You will have a difficult time knowing who your best friends are.吧``把your写成了you
不可以把are放与your之后.
如果照你那么说,从句就是：who your are best friends.
这显然不通,你翻译都不知道什么意思嘛.如果是疑问语序,谁是你的好朋友应该是：who are your best friends.
但因为这里是从句,所以要用正常语序：who your best friends are.
希望你可以懂```