I was about to leave the office ______ an unexpected visitor came.
| A．while | B．as | C．when | D．before |
Young Lee learned some English when she stayed in America, and last year she ____ herself Japanese.
| A．kept on teaching | B．went on teaching |
| C．kept on to teach | D．went on to teach |
_______ my opinion, you shouldn’t go there by yourself.
| A．On | B．To | C．In | D．At |
______ the beginning of the meeting, we heard a report by Mr Li.
| A．By | B．In | C．At | D．On |
It’s getting late. We must "be off" now. Which of the following can’t replace the underlined part?
| A．begin | B．be leaving | C．start | D．go |
----- The flower is beautiful. ----- _________.
| A．So is it | B．So it is | C．It is so | D．So it is |