21) ---- on a clear day,far from the city crowds,the mountai

21) ____ on a clear day,far from the city crowds,the mountains give him a sense of infinite peace.A) If walking B) While walking C) Walking D) When one is walking 22) I understood you were third-year students ____ in English.A) who majors B) who major is C) have majored D) majoring 23) A cool rain was falling,____ with snow.A) mixed B) mixing C) to mix D) having mixed 24) ____ by the police,the kidnappers had no choice but to surrender.A) Surrounded B) Surrounding C)having surrounded D) To be surrounded 25)____ equal educational opportunities,American Indians in the reservations remained backward and illiterate for a long time.A) Deprived off B) Depriving off C) Deprived of D) Depriving of