When leaving your car, how do you secure it against unauthorised use?

You answered correctly. To secure your car against unauthorised use when leaving it, you must lock the doors and close the windows. Locking the doors prevents others from entering, and closing the windows stops anyone from reaching in to unlock the vehicle or take items. The child-safety lock is only for securing children inside the car and does not prevent unauthorised access from outside, so it is not necessary in this situation. Always remember to fully secure your vehicle by locking all doors and closing all windows whenever you leave it unattended.