[
    {"ID":1001,"PreTechs":[]},
    {"ID":4001,"PreTechs":[[1001,1]]},
    {"ID":3002,"PreTechs":[[1001,1]]},
    {"ID":3001,"PreTechs":[[4001,1]]},
    {"ID":2002,"PreTechs":[[3002,1]]},
    {"ID":2001,"PreTechs":[[3001,1]]},
    {"ID":7001,"PreTechs":[[2002,1]]},
    {"ID":7002,"PreTechs":[[2001,1]]},
    {"ID":7003,"PreTechs":[[7001,1]]},
    {"ID":5001,"PreTechs":[[7002,1],[7003,1]]},
    {"ID":4002,"PreTechs":[[5001,1]]},
    {"ID":6001,"PreTechs":[[5001,1]]},
    {"ID":6002,"PreTechs":[[5001,1]]}
]