It is required that all traffic participants should __ the traffic rules to make traffic safer and faster.
| A．perform | B．possess | C．observe | D．Support |
Not only_______polluted but_______crowded.
| A．was the city;were the streets | B．the city was;were the streets |
| C．was the city;the streets were | D．the city was;the streets were |
—Are you going to see the film with us?
—If Mary wants to go，_______.
| A．so do I | B．so will I | C．I also go | D．so I will |
Not until_______to work，_______how much time I had wasted.
| A．did I begin;did I realize | B．did I begin;I realize |
| C．I began;did I realize | D．I began;I realize |
No sooner_______to bed_______I went to sleep.
| A．had I gone;when | B．I had gone;than |
| C．had I gone;than | D．I went;when |
_______，the farmers continued working in the fields.
| A．Late as it is | B．Late as it was |
| C．Though late it was | D．Although it was as late |