keep track of 追踪；记录；保持联系；密切注意…的动向

【例句】
It's hard to keep track of the children's comings and goings.
这些孩子来来往往，很难追踪他们的行踪。

Police keep track of the kidnapper using electronic surveillance equipment.
警方利用电子监视设备跟踪绑架者。