I've been tracking down my missing RV.我一直在寻找我丢失的房车
track down跟踪追捕; 追查
I'm trying to track down my old Aunt Maud.
我正试图寻找到我那年迈的婶婶莫德。
It took the police several days to track down their quarry.
警方用了几天时间追查到案中目标。
She's been covering for him.她一直在给他打掩护
cover for 为 ... 打掩护
His business was a cover for drug dealing.
他的商行是进行毒品交易的幌子。
Can you cover for me on friday?
星期五能不能请你替我个班?