He traced that number back to an empty apartment,他追蹤那個號碼找到了一個空的公寓

track down追捕到，追查出；追尋；查獲

She had spent years trying to track down her parents.
她已經(jīng)花了好多年時間試圖追尋父母的下落。

He was determined to track down the cause of food spoilage.
他決心查出食品腐爛的原因.

the landlord said that it was rented out to a girl.房主說以前出租給了一個女孩
rent out租出；出租
She decided to rent out a room to get extra income.
她為獲得額外收入決定租出一個房間.
They had to rent out the upstairs to make mortgage payments.
他們不得不將二樓租出去以償付抵押借款.

He's on his way back from New York right now.他現(xiàn)在正從紐約趕回來
on one's way在路上，在途中

She picked up her bag, and went on her way.

她提起包繼續(xù)趕路。

On her way back, she dropped by her brother's house.
在回家途中她順便到弟弟家看看.