______ scientists have learned a lot about the universe, there is much we still don't know.
| A．Once | B．Since | C．Though | D．Unless |
21、Animals do not “talk” with words. They use smells, sounds and movements to communicate with ____ animal.
| A．any other | B．another | C．each other | D．the other |
13、Some people would rather ride bikes as bike ridding has ___of the trouble of taking buses.
| A．nothing | B．none | C．some | D．neither |
12、The Parkers bought a new house but___ will need a lot of work before they can move in.
| A．they | B．it | C．one | D．which |
11、---- Excuse me, I want to have my watch fixed, but I can’t find a repair shop.
---- I know ____nearby. Come on,I’ll show you.
| A．one | B．it | C．some | D．that |
10、Even if they are on sale, these refrigerators are equal in Price to___, if not more expensive than,at the other stores.
| A．anyone | B．the others | C．that | D．the ones |