Mr. Evens works in Sydney. Last week he had a two weeks' holiday, but he didn't know where to go. He said to his friend Robert, "I hate the hot weather here, but I can't find a cool place in Australia. How will I take my holiday?" "That's easy," said Robert. "You'd better go to Moscow. Snow and ice are covering the ground now." Mr. Evens agreed with his friend. He bought an air ticket and soon arrived in Moscow. He made a happy journey  there. But one day He got into trouble. After lunch he went to a park outside the city. He saw a dog following him while he was walking past a house. It was hungry and wished him to give it some food to eat. Bad luck! He had no piece of bread or cake in his pockets. He tried to send it away, but it began to bark at him. He wanted to look for a stick but couldn't find anything except snow and ice. Suddenly he saw a stone in the ground. He tried to pick it up but he failed. "How strange Russians  are!" Mr. Evens said to himself. "They do not tie their dogs, but firmly  tie the ground!" Mr. Evens couldn't find a stick because   _  .
there weren't any trees in Moscow in winter the ground was covered with snow and ice the Russians had taken all the sticks home the Russians didn't tell him about it