It was getting late by the time Sam and Marco approached the summit, on (1) .......of the terrible weather on their way up. In (2)..........to high winds that nearly swept them right off the mountain, they faced freezing temperatures and heavy snowfalls. And (3)......... neither of them had any thoughts of giving up. In (4) ..........of the awful conditions they were determined to keep climbing even (5) ...................every step was now a huge effort, (6)............... to the fact they were so high up and the air was so thin. As (7) ..........as that, Marco was feeling quite ill, probably (8) ............of the height and a lack of food. But they knew that (9).......... reach the top they couldn’t stop for anything, even meals. They also knew that (10) ..............they got there this time, they would probably never have another chance to try. And Sam was sure that as (11)........... as they could begin going down by three o’clock, they would make it safely back to base camp that night – (12)........... they would both be very, very tired.