Though the key was pressed, nothing ______ on the screen.
| A．appeared | B．was appeared | C．appears | D．is appeared |
Yesterday evening I was playing the piano________the doorbell rang．
A．when
B．before
C．while
Tony________TV when his mother came in．
| A．watch |
| B．watches |
| C．was watching |
| D．is watching |
I saw him in the library yesterday．He________a book at that moment．
| A．reads |
| B．is reading |
| C．was reading |
| D．will read |
（北京）—What were you doing when we were playing basketball yesterday afternoon?
—I________the classroom．
| A．was cleaning |
| B．have cleaned |
| C．will clean |
| D．clean |
My alarm didn’t________．So I woke up late．
| A．put off |
| B．go off |
| C．take off |
| D．get off |