in which case主要用于引導非限制性定語從語，相當于 and in that / this case，其意為“如果是那樣 / 這樣的話。如：

She may be late, in which case we ought to wait for her. 她可能遲到，因此我們應該等她。

He may be busy, in which case I’ll call later. 他可能忙，如若如此，我以后再來拜訪。

I may have to go into hospital, in which case I won’t be going on holiday. 我可能要住院，如果那樣我就不去度假了。

I may have to work late, in which case I’ll telephone. 我可能得晚點下班，那樣我會打電話的。

Sometimes feta is very salty, in which case no salt needs to be added. 有時，羊奶干酪很咸。如果這樣的話，就不必加鹽了。

【注意】不能想當然地在 in which case 加上并列連詞。如：

我可能要住院，如果那樣我就不去度假了。

誤：I may have to go into hospital, and in which case I won’t be going on holiday.

正：I may have to go into hospital, in which case I won’t be going on holiday.

正：I may have to go into hospital, and in that case I won’t be going on holiday.