英语句子中时间修饰谁?

英语句子中时间修饰谁?
I have to cash my check at the bank before it closes at 4.
这个句子意思是
...bank closes at 4 还是
...I have to cash my check at 4

当然是bank closes at 4
如果修饰i cash at 4
应该是:
I have to cash my check at the bank at 4 before it closes.