--- How long do you think it is he arrived here?
--- No more than half a year, I believe.
| A．when | B．that | C．before | D．since |
Our math teacher, however, _____ speak English well.
| A．doing | B．does | C．is doing | D．was doing |
Your mother, however, ____ say that to us that day.
| A．does | B．did | C．is doing | D．was doing |
An awful accident, however, _____occur the other day.
| A．does | B．did | C．has to | D．had to |
What do you imagine _____ him from going?
| A．to prevent | B．preventing | C．to have prevented | D．prevented |
Who do you guess _____ to the station to meet her?
| A．to go | B．going | C．to have gone | D．went |