/give @p command_block 给予一个命令方块，命令方块设置为重复、无条件、始终活动

/execute as @a at @s run fill ~-20~-9~-20~20~9~20 diamond_ore replace dirt 泥土变钻石矿

/execute as @a at @s run fill ~-20~-9~-20~20~9~20 diamond_block replace grass 草方块变钻石块

/kill @e [type=item] 清除掉落物

/gamerule commandblockoutput false 防刷屏

/tickingarea add x y z x y z   设置常加载区块，xyz代表坐标