二.合作探究
(学生：Skimming the reading passage and find：
1. What is the type of the passage?
2. First put the following machines in an order according to the time when they appeared, then check the answer after reading the passage.
( ）analytical machine
( ) calculating machine
( ) robot
( ) PC
( ) universal machine
( ) laptop
3. Listening to the reading passage and finding the main idea of it
