WHY DO CLIMBERS ON MOUNT EVEREST CARRY BOTTLES OF OXYGEN

5. - DE THI OLYMPIC MON TIENG ANH LOP 6 TRUONG CHUYEN HA NOI AMSTERDAM NAM 2011 5. - DE THI OLYMPIC MON TIENG ANH LOP 6 TRUONG CHUYEN HA NOI AMSTERDAM NAM 2011
Lớp 6 Tiếng Anh DE THI OLYMPIC MON TIENG ANH LOP 6 TRUONG CHUYEN HA NOI AMSTERDAM NAM 2011
5. Why do climbers on Mount Everest carry bottles of oxygen?A. The weather is cold. B. Climbing makes them tired.C. The air is very thin. D. They are thirsty.