我在清理书桌时偶然发现了这些照片。

I ___stumbled ___across these photographs while I was cleaning out my desk.

经过数月浏览房产网站和周末看房，我们终于在薰衣草路偶然发现了这座惊人的排屋末端房屋。

After months of property website surfing and house-hunting over weekends, we finally ___stumbled ___upon this amazing end of terrace house in Lavender Road.

她在阁楼上偶然发现了一本旧日记。

She ___stumbled ___on an old diary in the attic.