diff --git a/recipe/transfer_queue/ray_trainer.py b/recipe/transfer_queue/ray_trainer.py
index d19b3d5b3d1..df855e70a9b 100644
--- a/recipe/transfer_queue/ray_trainer.py
+++ b/recipe/transfer_queue/ray_trainer.py
@@ -361,7 +361,7 @@ def __init__(
 
     def _initialize_data_system(self):
         num_n_samples = self.config.actor_rollout_ref.rollout.n
-        # 1. 初始化TransferQueueStorage
+        # 1. initialize TransferQueueStorage
         total_storage_size = self.config.data.train_batch_size * self.config.trainer.num_global_batch * num_n_samples
         self.data_system_storage_units = {}
         storage_placement_group = get_placement_group(self.config.trainer.num_data_storage_units, num_cpus_per_actor=1)
@@ -373,8 +373,9 @@ def _initialize_data_system(self):
             self.data_system_storage_units[storage_unit_rank] = storage_node
             logging.info(f"TransferQueueStorageSimpleUnit #{storage_unit_rank} has been created.")
 
-        # 2. 初始化TransferQueueController
-        # 这里支持多controller实例以实现负载均衡，支持大规模扩展。不同controller可分配至不同RL计算任务
+        # 2. initialize TransferQueueController
+        # we support inilialize multiple controller instances for large-scale scenario. Please allocate exactly
+        # one controller for a single WorkerGroup.
         self.data_system_controllers = {}
         controller_placement_group = get_placement_group(self.config.trainer.num_data_controllers, num_cpus_per_actor=1)
         for controller_rank in range(self.config.trainer.num_data_controllers):
@@ -388,8 +389,7 @@ def _initialize_data_system(self):
             )
             logging.info(f"TransferQueueController #{controller_rank} has been created.")
 
-        # 3. 将Controller注册至各个Storage
-        # 每个Storage Unit拿到所有Controller的handler，通过Ray拿到对应的IP+端口，之后建立ZMQ Socket进行消息传输
+        # 3. register controller & storage
         self.data_system_controller_infos = process_zmq_server_info(self.data_system_controllers)
         self.data_system_storage_unit_infos = process_zmq_server_info(self.data_system_storage_units)
 
@@ -400,11 +400,11 @@ def _initialize_data_system(self):
             ]
         )
 
-        # 4. 创建Client
+        # 4. create client
+        # each client should be allocated to exactly one controller
         self.data_system_client = AsyncTransferQueueClient(
             client_id="Trainer",
             controller_infos=self.data_system_controller_infos[0],
-            # TODO: 主控Client感知所有controller，WorkerGroup和Worker的Client感知一个controller
             storage_infos=self.data_system_storage_unit_infos,
         )
 
@@ -1472,7 +1472,9 @@ def fit(self):
                         log_rollout_meta.reorder(balanced_idx)
                         self._log_rollout_data(log_rollout_meta, reward_extra_infos_dict, timing_raw, rollout_data_dir)
 
-                # validate
+                # TODO: clear meta after iteration
+
+                # TODO: validate
                 if (
                     self.val_reward_fn is not None
                     and self.config.trainer.test_freq > 0