—Why are you so nervous?

    —To our great surprise, we found        by the strangers.

    A．we monitored                        B．ourselves monitored

    C．us to monitor                       D．ourselves monitoring

―Why are you so nervous?

―To our great surprise, we found        by the strangers.

       A. we monitored                                            B. ourselves monitored

       C. us to monitor                                             D. ourselves monitoring

—Why are you so nervous?
—To our great surprise, we found       by the strangers.