lost track of

• v. 忘记(失去 ... 的线索)

lost track of的用法和样例：

例句

1. His plane was lost track of about two hours out from London Airport.
   他的飞机飞出伦敦机场已约有两个小时没有音信了。
2. It's hard to keep track of all one's old school friends. I have lost track of some of mine already.
   很难保持与所有老同学的联系，我已失去与一些老同学的联系了。