The Grammaring Guide to English Grammar with Exercises

Sentential relative clause

A sentential (also called connective) relative clause does not refer to a preceding noun; it rather comments on the whole preceding clause or sentence:

The streets were empty,

which was unusual for this time of day

.

(The fact that the streets were empty was unusual.)

In conversation, a sentential relative clause may also be interjected by another speaker:

"Then he goes on to say how much he appreciates all the effort we've put into it." "

Which is strange

because he never seemed to care much about what we do."