if语句将用作简单的错误控制，如果由于用户的小失误而导致它未找到文件，则退出脚本。

The if statement ACTS as simple error control, exiting our script if it does not find the file with a somewhat graceful error for our users.

youdao

如果计算所得的降水像素超出阈值参数，则退出循环并输出“raining”状态。

If enough precipitation pixels have been counted to exceed the threshold parameter, exit the loops and write the "raining" status.

youdao

我告诉他，如果他退出那么他要自负其则。

I told him if he withdrew it was on his own account.

《柯林斯英汉双解大词典》