If left unchecked, weeds will flourish.

如果不加遏制，杂草就会疯长。

《柯林斯英汉双解大词典》

The plant will soon choke ponds and waterways if left unchecked.

如不控制这种植物的生长，池塘和水道很快就要被阻塞。

《牛津词典》

Without a good process, this is a recipe for chaos which, left unchecked, will doom a SOA project to failure.

如果没有良好的流程，这就会导致一片混乱，如果不对其进行检查，将会导致SOA项目失败。

youdao

Within 20 years Medicare outlays, left unchecked, will crowd out all other federal budget items except defense.

FORBES: Magazine Article

Left unchecked, the next decade is shaping up to be a rough one for Harry and Louise.

FORBES: Health Care Reform

Entitlement beliefs that are left unchecked lead to selfish, even more entitled expectations.

FORBES: Entitlements in Business Should Never Replace Merit