Nonstationarity
非平稳性
🗣️ 情景例句
If I fail this test I'll kill myself.
我这次考试要是通不过，就得自杀了。
I wish you had called me back the next day,as I had asked you to.
我希望你明天打电话给了我回来,正如我要你做的。
We have an old musical instrument.
我家有件古乐器，