做事必须留一手 (Pull a Punch)

大千世界，复杂多变，一方面要求做人立世必须有真本领，另一方面，有了真本领又不可轻易拿出，一旦在不适当的时机和场合亮出看家的本领，被人看到了自己压箱底的绝活，就会被别人及时防范，以后再用的时候就不灵了，为人处世要有"王牌"，更要有"底牌"。看家的本领不可盲目轻率地拿出来，要在关键时刻才出手。Facing a big, complex and unpredictable world, we must have real knacks in life and work on the one hand, but also learn to use them as the last resort. Once you expose such aces up your sleeve at an improper timing or occasion, others would take timely precautions, which would leave your wares ineffective for future uses. Be it in life or work, you should possess your "trump card" and, better still, good "pocket card", which should not be revealed in a blind and reckless manner, but should only be put out at critical junctures.