a tall order

基本解释

I know it sounds like a tall order, but remember; this is your quality of life we are talking about.
我知道这听起来好像遥不可及，但是请记住：这就是我们在讨论的生命特质。
It’s a tall order, and at the moment Vietnam is seen as a production base for lower value-added goods like textiles, furniture or footwear.
他的这一想法未免太过苛求。当前，越南主要被视为低附加值商品如纺织产品、家具、鞋袜等的生产地。
Undoubtedly, this is a tall order – but I see this as the real challenge we need to confront and overcome.
毫无疑问，这是个很高的要求，但我认为，它是我们需要面对和战胜的真正挑战。

General McChrystal comes to Afghanistan with a tall order from President Barack Obama.
It's a very tall order that he claims for himself.
他自称的角色是极端苛求的。
耶鲁公开课 - 政治哲学导论课程节选

Now, the economy has to cooperate as well, and that seems a tall order.
FORBES: Search & Rescue
Answering them is a tall order, something that I will tackle in future columns.
FORBES: "Cloud Don'ts": Advice to Avoid Wasted Investment