电火花计时器所用的电源是50 Hz的交流电，其相邻点间的时间间隔是T，若纸带上共打出N个点，纸带上记录的时间为t，则下列各式正确的是 [ ]

A．T=0.1s，t=NT

B．T=0.05s，t=（N-l）T

C．T=0.02s，t=（N-l）T

D．T=0.02s，t=NT

I went to see the film last night. It was the second time that I ______ the film. [ ]

A. have seen

B. saw

C. see

D. had seen