[Doc] Translate docs (#575)

docs/faq.md

@@ -5,6 +5,7 @@
 Some intermediate variables are used in the configs files, like `train_pipeline`/`test_pipeline` in datasets.
 
 For example, we would like to first define the `train_pipeline`/`test_pipeline` and pass them into `data`. Thus, `train_pipeline`/`test_pipeline` are intermediate variable.
+
 ```python
 ...
 train_dataset_type = 'SRAnnotationDataset'

docs_zh-CN/faq.md

@@ -1 +1,61 @@
 ## 常见问题解答
+
+### 在配置中使用中间变量
+
+配置文件中使用了一些中间变量，如数据集中的 `train_pipeline` 和 `test_pipeline`。
+
+例如，我们通常先定义 `train_pipeline` 和 `test_pipeline`，再将它们传递到 `data` 中。因此， `train_pipeline` 和 `test_pipeline` 是中间变量。
+
+```python
+...
+train_dataset_type = 'SRAnnotationDataset'
+val_dataset_type = 'SRFolderDataset'
+train_pipeline = [
+    dict(
+        type='LoadImageFromFile',
+        io_backend='disk',
+        key='lq',
+        flag='unchanged'),
+    ...
+    dict(type='Collect', keys=['lq', 'gt'], meta_keys=['lq_path', 'gt_path']),
+    dict(type='ImageToTensor', keys=['lq', 'gt'])
+]
+test_pipeline = [
+    dict(
+        type='LoadImageFromFile',
+        io_backend='disk',
+        key='lq',
+        flag='unchanged'),
+    ...
+    dict(type='Collect', keys=['lq', 'gt'], meta_keys=['lq_path', 'lq_path']),
+    dict(type='ImageToTensor', keys=['lq', 'gt'])
+]
+
+data = dict(
+    # 训练
+    train_dataloader = dict(
+        samples_per_gpu=16,
+        workers_per_gpu=6,
+        drop_last=True),
+    train=dict(
+        type='RepeatDataset',
+        times=1000,
+        dataset=dict(
+            type=train_dataset_type,
+            lq_folder='data/DIV2K/DIV2K_train_LR_bicubic/X2_sub',
+            gt_folder='data/DIV2K/DIV2K_train_HR_sub',
+            ann_file='data/DIV2K/meta_info_DIV2K800sub_GT.txt',
+            pipeline=train_pipeline,
+            scale=scale)),
+    # 验证
+    val_dataloader = dict(samples_per_gpu=1, workers_per_gpu=1),
+    val=dict(
+        type=val_dataset_type,
+        lq_folder='data/val_set5/Set5_bicLRx2',
+        gt_folder='data/val_set5/Set5_mod12',
+        pipeline=test_pipeline,
+        scale=scale,
+        filename_tmpl='{}')
+
+empty_cache = True  # 在每次迭代后清空缓存。
+```