Question 1: C. unpolluted
→ Fresh = Unpolluted (adj.): trong lành, không ô nhiễm
Question 2: B. continued
→ Go on = continue (v.): tiếp tục
Question 3: D. interesting
→ Exciting = Interesting (adj.): thú vị
Question 4: C. landed
→ Take off = land (v.): hạ cánh