vi.

1. 探究，鑽研；搜索[（+into）]
   delve into the background of a case

   探究某事的背景

2. 【英】【古】挖，掘

vt.

1. 【英】【古】挖，掘；刨（地）

n.

1. 【古】（挖成的）洞，穴[C]

v.

1. reach inside a receptacle and search for something.
2. research intensively into something.