将一个英语语料库分成训练集和测试集，随机分配8:2的比例。
file_path: str = "/path/to/corpus.txt"
split_ratio: float = 0.8
```python
import random

with open('/path/to/corpus.txt', 'r', encoding='utf-8') as f:
    lines = f.readlines()

random.shuffle(lines)
split_index = int(len(lines) * 0.8)

train_lines = lines[:split_index]
test_lines = lines[split_index:]

with open('/path/to/train.txt', 'w', encoding='utf-8') as f:
    f.writelines(train_lines)

with open('/path/to/test.txt', 'w', encoding='utf-8') as f:
    f.writelines(test_lines)
```