凡事不可半途而废: do nothing by halvesdon't claim to know what you don't know
凡事开头难: getting things started is always difficult.; a good lather is half a shave.; it is the first step that costs.; nothing is easy in the beginning.; the first blow [stoke] is half the battle.
凡事只能量力而行: a man can never thrive who had a wasteful wife
