outline:1.my opinion.2.the advanteges.3.draw a conclusion.I think the most useful invention is compater .Computer is a very useful tool in our life,in our study as well as works.For example ,computer can send some messages to foreign friends by E-mail.The computer can open our eyes to let us know more.
Computer is the most helpful invention in the world.Computer can help us in study or work.There are many computer functions（功能）We can listen to music or play the game on computer.It make us relax.
More importantly,The computer can open our eyes to let us know more.