At present, both are common in most cases, but it is difficult to attack. Now it refers to technical difficulty, and attacking the enemy is a solid fortification.

"Strong" and "difficult" are homophones, but their meanings are different. Listening to the leaders' speeches, we often hear the saying that "we should concentrate our efforts and overcome difficulties". Firm, which means firm and unshakable; Difficult is difficult.

To "attack" is to overcome difficulties and conquer fortresses. 1977, "the spring of science" came, and Ye Shuai wrote a poem: "You are not afraid to attack the city, but you are not afraid to attack books. If there are obstacles in science, efforts can pass. "

Attack Gūngjiān( 1): attack a strong enemy or an enemy's defense accident. Anyone who uses troops will be weak (soft and lazy) when attacking, and will be god when taking advantage of defects. -"Pipe System" (2): Make great efforts to break through scientific and production technical problems. Overcoming difficulties means overcoming difficulties and hardships, which refers to the environment; And overcoming difficulties means overcoming difficulties.