From a discussion at Lang-8:
Kim and I ran fast as we could, but we missed the bus, which made us late for school.
I believe the sentence's use of the relative clause to be okay: the relative pronoun which refers to the whole preceding clause "but we missed the bus".
But both the author of the post and one other non-native English speaker believe this use of which to be erroneous, since in their view the antecedent is bus: "the bus made us late for school."
Gleb quoted a SAT preparation course in which the following use of which is apparently described as erroneous:
"Marylin and I ran as fast as we could, but we missed our train, which(C) made us late for work."
... Which is a pronoun, and needs a noun as its antecedent. The only available noun is train, but that doesn't make sense ... So there is your error, choice C.
Is that really so? In Michael Swan's PEU, topic 494.9 says that which can relate to the whole of a preceding clause. I'm a bit baffled. Is this a typo in the SAT course, or am I missing some point?