A tall poplar tree has its roots rooted in the yellow sand and stones of the desert. Like a flag, like a mountain, like a sentinel on guard.
Personal experience: If the subject is "white lilac", trees, grass, etc. can be used in imitation; if the predicate is "open", trees can be written with roots. Also pay attention to the consistent sentence structure during imitation.
Good luck with the exam~ I hope my answer will be helpful to you~~~