幸好...不然...
[主语/条件] + 幸好 + [动词/短语] + 不然
Core sentence pattern in modern spoken Mandarin.
[Authentic Cinema Evidence Base]
(2 clips)
00:02
(出去 到车上等着) ── Previous context
“It's a good thing I was here, or you'd be fuckin' dead.”
00:02
(王爷) ── Previous context
“It was fortunate you had me patrol the streets on the Emperor's birthday.”