The auto company succeeded in developing a new type of new energy vehicle, ________ countless failure.
A. experiencing B. to experience C. to have experienced D. having experienced
My parents walked the pet dog several times a day, getting exercise they otherwise_________.
A. wouldn’t have B. wouldn’t have had C. didn’t have D. hadn’t had
—Look, this is the bestseller everyone’s been talking about for the last two months.
—How in the world ___________ a copy?
A. are you getting B. were you getting C. did you get D. had you got
In the past few decades, scientists have made a great ________ in the treatment of cancer.
A. breakout B. breakdown C. breakup D. breakthrough
Volunteers are making use of every minute to________ their foreign languages because language volunteers must pass a written test and an interview.
A. put up B. polish up C. take up D. make up
Leaving the door unlocked is an open _________ to burglars(夜盗).
A. adaptation B. transformation C. invitation D. participation
