| Form | Example | |
|---|---|---|
| Reduced active | drop who/which + be → -ing | people working here |
| Reduced passive | drop who/which + be → -ed | letters sent yesterday |
| Prepositional | informal: end / formal: prep + whom/which | to whom I spoke / I spoke to |
| Clause-which | comma + which (not that) | ..., which was unexpected |