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
（2013天津）I saw him in the library yesterday．He________a book at that moment．
A．reads
B．is reading
C．was reading
D．will read
（2014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
There is a ruler on the ground．Please________．
A．pick up it
B．pick it up
C．pick up them
D．pick them up
