恩格斯指出:“全部哲学特别是近代哲学的重大基本问题,是思维和存在的关系问题。”恩格斯的论断指出了( )
—How long does it take you to go to the bus station? —______.
Sam has a bike. He ______ it to school every day.
For some students, it’s difficult ______ school.