[英語慣用語] uphill battle (一場艱苦/上坡的戰鬥)
When you are walking uphill, you may feel tired and it is quite difficult to go up. Thus, if anything is described as an uphill battle, it means you have a difficult time accomplishing it.
uphill = 是上坡的意思,引伸為艱難的,費力的
battle = 戰鬥
The verb used with it is "fight" as in "fight an uphill battle."
e.g. Taiwan's economy is fighting an uphill battle as China and South Korean take over more and more of its export market.