The field research will take Joan and Paul about five months; it will be a long time _____ we meet them again.
| A．after | B．before |
| C．since | D．when |
It is always difficult being in a foreign country, __________if you don’t speak the language.
| A． extremely | B．naturally | C．basically | D．especially |
It is generally believed that teaching is ___________it is a science.
| A．an art much as | B．much an art as | C．as an art much as | D．as much an art as |
Several weeks had gone by____________I realized the painting was missing.
| A． as | B． before | C． since | D． when |
_______________you call me to say you’re not coming, I’ll see you at the theatre.
| A． Though | B． Whether | C． Until | D． Unless |
After she considered the problem, she got a tall box to stand ________.
| A． on | B．up | C．above | D．by |