22. —Mr. Smith _____ in Russia for 10 years. —No wonder he can speak Russian fluently and now teaches Russian in a Chinese college.had stayed B. has stayed C. stayed D. stays
All animals in nature must learn to to a changing environment in order to survive.
Paul was not allowed to work he was fully recovered from the flu.
Assistance dogs are trained to help disabled to live more independent life.
— Leo, I finally persuaded my mother. — So we can go to the basketball club tonight.
Had he studied harder, he______the final exams.