Which is more suitable for this sentence?
What is 1000km to them _____they can fly an hour?
I dont know the exact meaning of this sentence,please explain!
Thank you !
更新1:
Sorry , I want you to explain the exact meaning of two words and the meaning of this sentence !Thankyou . Also your answer was wrong! It shouldnt be as ,the answer of my answer book is since .But I still dont know the meaning of this sentence.....
