Shifting of dune had horizontal direction (ne SW) and longitudinal direction (NW SE) and irregular formation formed with varied wind direction.

沙丘走向有横向(NE - SW)和纵向(NW - SE)以及多风向形成的不规则形。

youdao

Therefore, river evolution has very vital initiative and promoting effects on the formation and development of sand-dune groups and sandy land in natural conditions.

这些足以说明，在自然状况下，河流演变在沙丘群和沙地形成演化中起着非常重要的促进作用。

youdao