单项选择题

We've done once but failed. We'll have to do it()time.

A. a second
B. the second
C. the twice
D. twice

相关考题

Both Tom and Mary （） the exam.A. has passedB. have past...

单项选择题Both Tom and Mary （） the exam.

A. has passed
B. have past
C. have passed
D. had passed