— Why is the chemical plant closed?
— Because large quantities of waste water ______ into the Yangtze River.
| A．has been released | B．is being released |
| C．was released | D．have been released |
He was observed __________ into the house and help himself to what he liked before the owner came back.
| A．to slide | B．slide |
| C．sliding | D．slid |
Hospital staff burst into cheers after doctors completed a 20-hour operation to have_______ one- year-old twins at the head.
| A．accomplished | B．separated |
| C．divided | D．removed |
Hearing the dog barking fiercely, away __________.
| A．running the thief | B．was running the thief |
| C．the thief was running | D．ran the thief |
This basketball team had lots of excellent players, so its fans had never expected that it ________ have failed in the final.
| A．would | B．might |
| C．should | D．could |
Failure hurts grownups and children, but it can make a ________ contribution to your life once you learn to use it.
| A．positive | B．thorough |
| C．enjoyable | D．chief |