The river _____ banks used to be covered with fruit trees and flowers is now seriously polluted.
| A．of which | B．along which | C．where | D．whose |
I regret _____ hard at school, or I would have succeeded in passing the exam.
| A．not to work | B．having not worked | C．to have not worked | D．not having worked |
. We should prevent such a silly mistake _____ again.
| A．occurring | B．to occur | C．to be occurred | D．from being occurred |
_____ full preparations, we decided to put off the meeting till next week.
| A．We did not make | B．Having not made | C．We had not made | D．Not having made |
I’m examining the article he has just finished _____ the possible mistakes in it.
| A．being corrected | B．to correct | C．corrected | D．having corrected |
Having passed all the tests, she felt a great weight _____ off her mind.
| A．taking | B．taken | C．take | D．to be taken |