When he came in, I happened __________ my experiment in the lab.
| A．to do | B．to be doing |
| C．to have done | D．to be done |
推荐试卷
When he came in, I happened __________ my experiment in the lab.
| A．to do | B．to be doing |
| C．to have done | D．to be done |
试题篮
()
粤公网安备 44130202000953号
