Some sections have been hollowed out over time, and are sagging 4. Grass and tree roots that have infiltrated 5 gaps pose another major threat to their stability.

随着时间的流逝，部分城墙出现空心区、正在塌陷。长在城墙缝隙之间的草、树根也对墙体的稳固构成威胁。

youdao

One is to trace your ancestry back through humanity's family tree to its roots in North-East Africa (an offer like that of the Genographic Project, described later in this report).

一种是通过根源于北-西非的人类家族树以追溯祖先起源(有关此类提供基因成像的服务项目请关注后续报道)。

youdao

I considered that the air temperature has risen to 35 degrees, so the temperature of the tree roots must also be very high!

想那气温已达35度，树根的温度也很高吧？

youdao

It is true, they say, that tree roots can trap sliding soil but only for shallow landslides of up to a metre in depth.

ECONOMIST: Deforestation and floods

Today, it is blissfully quiet - though back in town, on the elegant Rue St-Louis, there is a cannonball still wedged in the roots of a tree that is said to date from that battle.

BBC: Qu��bec's wood runners

New York has experienced only 2.06 inches of rain the past 20 days after a winter that set records for snow, which funneled water to tree roots.

WSJ: Sniff, Sneeze, Blow, Wipe, Repeat