1．—How many elephants did you see?
—________．
A．No one B．Nothing C．None D．Neither
2． I have lost my pen． I can’t find ________． I have to buy ________．
A．it；it B．one；one C．one；it D．it；one
3．It is not rare in ________ that people in ________ fifties are going to university for further education．
A．90s；the B．the 90s；the C．90’s；their D．the 90’s；their
