－ I don't understand why you didn't go to the lecture yesterday afternoon.
－ I'm so sorry, but I ________ my homework.
A. have done B. am doing
C. would do D. was doing
—Haven't seen you for ages! Where have you been?
—I went to Ningxia and there for one year, teaching as a volunteer.
A. stayed B. stay C. had stayed D. am staying
（题文）（2018·江苏）Hopefully in 2025 we will no longer be e-mailing each other, for we _______ more convenient electronic communication tools by then.
A. have developed B. had developed
C. will have developed D. developed
We were sleeping soundly when the alarm clock ________ and woke everyone.
A. went off B. went by
C. went over D. went up
Over the last three decades, the number of people participating in physical fitness programs ________ sharply.
A. was increasing B. has increased
C. had increased D. will be increasing
－ Henry isn't quite himself today. He seems to be so tired.
－ He said he had worked on his project ________ the whole night.
A. over B. with
C. through D. in
