After several years of observation, the research group ______ the conclusion that language acquisition is faster when students ______ to the situation where it is spoken.

After several years of observation, the research group ______ the conclusion that language acquisition is faster when students ______ to the situation where it is spoken.

1. A.
   has come to; expose
2. B.
   have arrived at; are exposed
3. C.
   has concluded; are exposed
4. D.
   have reached; expose

After several years of observation, the research group ______ the conclusion that language acquisition is faster when students ______ to the situation where it is spoken.

A. has come to; expose　　　　　　 B. have arrived at; are exposed

C. has concluded; are exposed　　　 D. have reached; expose

       After several years of observation, the research group ______ the conclusion that language acquisition is faster when students ______ to the situation where it is spoken.

A. has come to; expose                   B. have arrived at; are exposed

C. has concluded; are exposed         D. have reached; expose