big=massive(large in size， quantity， or extent)， colossal(use this word， you emphasize something’s large)， tremendous(INFORMAL)

　　avoid=shun(if someone shuns something， s/he deliberately avoid that something or keep away from it.)

　　difficult=arduous (if something is arduous， it is difficult and tiring， and involves a lot of efforts)

　　poor(soil)=barren， infertile(used to describe the soil is so poor that plants cannot be planted on it)

　　fragile=brittle， vulnerable(someone who is vulnerable is easily hurt emotionally or physically)

　　show=demonstrate (to demonstrate a fact means tp make it clear to people.)

　　fair=impartial(someone who is impartial is able to give a fair opinion or decision on something.)