That's a tall order to live up

That's a tall order to live up
That's a tall order to live up

That's a tall order to live up
这是一个很难做到的任务.a tall order :难办的事(或工作)；难以满足的要求
live up to :不辜负；做到；实践

那是一个做起来非常苛刻的订单