Resources
	"all missions.json”   （describe all the missions,how many missions,their names）
	mission1
		"mission.json” (describe this mission,how many steps,should talk to whick npc in each step,how many npcs)
		"npc1.json”   (the npc action,their dialog,and perform some choices)
		"npc2.json”
		"…”
	mission2
		"mission.json”
		"npc1.json”
		"npc2.json”
		"…”
	mission3
	…