马文才为赢得比赛，找上在街上卖字画的梁山伯，梁山伯家境清寒，为人十分诚实，坚决不肯作弊，后因书僮四九的劝说，才不得以答应。At that tail of the warhead, the drag armour-piercing firebomb is filled with a drag agent and a fireagent, Under the pressure of propellant propelling warhead, it will spontaneously ignite to produce open flame, So it can break through the oil drum and ignite or detonate the gasoline. However, the old-fashioned traced armour-piercing firebombs have obvious trajectories due to traced light when they are launched. Therefore, it is very easy to expose oneself while pointing targets to friendly forces. Therefore, the new tracer armour-piercing firebombs now equipped all start to burn and emit light only after the projectile flies out of the muzzle for a certain distance (the generally set safe distance is 100 meters, which makes it impossible for the enemy to judge the firing position with tracer ammunition, while targets within 100 meters do not need to be indicated by tracer), The principle is generally to ignite the tracer and combustion agent carried by the projectile by accumulating the heat generated by the warhead's friction with the air after flying for a certain distance to a certain extent.只要是看过这条微-博的人，便再也忘不了这两句。