Read the text and answer the questions that follow.
There was something strange about the sign. Alex hesitated for a moment, wondering what it was. Then he dismissed it. He was walking in the countryside and the sun was shining. What could possibly be wrong? He followed the sign. The path continued for about another quarter of a mile, then dipped down into a hollow. Here, the grass was almost as tall as Alex, rising up all around him, a shimmering green cage. A bird suddenly erupted in front of him, a ball of brown feathers that spun round on itself before taking flight, something had disturbed it. And that was when Alex heard the sound- an engine getting closer. A tractor? No. it was too high-pitched and moving too fast. Alex knew he was in danger the same way an animal does. There was no need to ask why or how. Danger was simply there. And even as the dark shape appeared, crashing through the grass, he was throwing himself to one side, knowing- too late now- what it was the had been wrong about the second footpath sign. It had been brand-new. The first sign, the one that had led him off the road, had been weather-beaten and old. Someone had deliberately led him away from the correct path and brought him here. To the killing field. He hit the ground and rolled into a ditch on one side. The vehicle burst through the grass, its front wheel almost touching his head. Alex caught a glimpse of a squat black thing with four fat tyres, a cross between a miniature tractor and a motor-bike. It was being ridden by a hunched-up figure in grey leathers., with helmet and goggles. Then it was gone, thudding down into the grass in the other side of him and disappearing instantly, as if a curtain had been drawn. Alex scrambled to his feet and began to run. There were two of them. He knew what they were now. He’d ridden similar things himself, on holiday, in the sand-dunes of Death Valley, Nevada. Kawasaki, four by fours powered by 400 cc engines with automatic transmission. Quad bikes. They were circling him like wasps. A drone, then a scream, and the second bike was in front of him, roaring towards him, cutting a swathe through the grass. Alex hurled himself out of its path, once again crashing into the ground, almost dislocating his shoulder. Wind and engine fumes whipped across his face. He had to find somewhere to hide. But he was in the middle of a field and there was nowhere apart from the grass itself.