We are flying at _____ altitude of 6,000 meters and perhaps we will get there at _____ midnight.
| A．the; the | B．an; the | C．an; / | D．the; / |
The theory he sticks to ______ to be of no use in our studies.
| A．proves | B．prove | C．proving | D．be proved |
____ that caused him to serve dinner an hour later than usual.
| A．It was we being late | B．It was our being late |
| C．It was we were too late | D．It was because we were late |
---- Do you know his address？
---- No, I also wish I _____ where he _____.
| A．knew, lived | B．knew, lives | C．know, lives | D．know, lived |
—John has put forward _______ most challenging question for us to answer.
—Yes, it really is. I have never heard _______ harder one.
| A．the; 不填 | B．不填; the | C．the; the | D．a; a |
Though _____, the news brought them much encouragement.
| A．surprised | B．being surprised |
| C．having surprised | D．surprising |