1、It is during this stage that the major surgery takes place.
主要手術(shù)就是發(fā)生在這個(gè)階段。

2、My mother underwent major surgery last year.
我母親去年動(dòng)過大手術(shù)。

3、Major surgery followed by a touch-and-go recovery
緊隨著大手術(shù)的危險(xiǎn)的恢復(fù)期