IT is hard to think of a world without metals什么句型

IT is hard to think of a world without metals什么句型 you think it is a good habit to study hard It is hard to imagine a large city without a policeman,but s 一道英语专四题：It is hard to imagine a large city without policemen It is _____(use)to talk much without working hard it is hard to say with or without you! This kind of machine is used ____ metals.A.to cutting B.for Welcome to the world of JK Rowling! It is a world of magic a It's hard to tell that the world we live in is either a real It's hard to tell the world we live in is either a reality o 英语.It's hard to tell that the world we live in is either a r think it hard to do 和 i think it's hard to do 有什么区别