My purpose is that how to run Bus in 10 seconds. Because my program is 3D simulation, it requires all objects must finish on time. If Bus doesn't finish in 10 seconds, Car will have to wait the Bus until it finish -> Car will be late. And if the model have some threads (as Truck move obj from C to D, ....), it will make the back threads run later.
Really, with your solution, Bus will not move to B after 10 seconds -> Car will not move to C after 20 seconds (plus 10 seconds of Car).