diff --git a/scene/little_game/书架/书架.gd b/scene/little_game/书架/书架.gd
index 93ed8aef..de1417e8 100644
--- a/scene/little_game/书架/书架.gd
+++ b/scene/little_game/书架/书架.gd
@@ -48,6 +48,20 @@ func _ready() -> void:
 	_measure_width_by_row()
 	# shuffle at the end
 	_shuffle_books()
+# 	# test
+# 	_test()
+
+
+# func _test():
+# 	var timer = Timer.new()
+# 	timer.autostart = true
+# 	timer.wait_time = 0.5
+# 	timer.one_shot = false
+# 	timer.timeout.connect(func():
+# 		print("[test] reload")
+# 		get_tree().reload_current_scene()
+# 	)
+# 	get_tree().root.add_child.call_deferred(timer)
 
 
 func _enter_tree() -> void:
@@ -92,30 +106,39 @@ func _shuffle_books() -> void:
 	rand_from_seed(Time.get_ticks_usec())
 	# 打乱偶数次有可能复原，需要打乱奇数次；为降低难度，仅打乱一次
 	var shuffle_times = 1
-	var r_size = current_answer[0].size()
+	var r_size := current_answer[0].size() as int
 	for _i in range(shuffle_times):
-		var col_1 = randi() % r_size
-		var col_2 = randi() % r_size
+		var col_1 := randi() % r_size
+		var col_2 := _rand_exclusive(col_1, r_size)
 		selected_book = [0, col_1]
 		_interchange_book(0, col_2, false)
 	_relocate_books(0)
 	r_size = current_answer[1].size()
 	for _i in range(shuffle_times):
-		var col_1 = randi() % r_size
-		var col_2 = randi() % r_size
+		var col_1 := randi() % r_size
+		var col_2 := _rand_exclusive(col_1, r_size)
 		selected_book = [1, col_1]
 		_interchange_book(1, col_2, false)
 	_relocate_books(1)
 	r_size = current_answer[2].size()
 	for _i in range(shuffle_times):
-		var col_1 = randi() % r_size
-		var col_2 = randi() % r_size
+		var col_1 := randi() % r_size
+		var col_2 := _rand_exclusive(col_1, r_size)
 		selected_book = [2, col_1]
 		_interchange_book(2, col_2, false)
 	_relocate_books(2)
-
 	# turn off initilazing after shuffle
 	suffling = false
+	_check_answer()
+
+
+func _rand_exclusive(exclude_id: int, size: int) -> int:
+	if size <= 1:
+		return 0
+	var id = randi() % size
+	if id == exclude_id:
+		return _rand_exclusive(exclude_id, size)
+	return id
 
 
 var press_mutex := Mutex.new()
@@ -186,8 +209,7 @@ func _interchange_book(row: int, col: int, relocate := true) -> void:
 	# relocate after reset selected_book
 	if relocate:
 		_relocate_books(row)
-	# check answer
-	if relocate:
+		# check answer after relocation
 		_check_answer()