An old yellow calendar made by excel.

16.a； 17.d； b； 1. Correct; 2 correct. 3. Incorrect (it can also be managed by computer); 4. Correct; 5. correct; 6. Incorrect (it should be the network); 7. Incorrect (information sources are extensive and difficult to distinguish); 8. Incorrect (patent infringement); 9. Incorrect (it should be a local security threat and an Internet security threat); 10. Correct; 1 1. is incorrect (the regularity and comparison of data should be described); 12. Incorrect (should be a function);

13. Incorrect (also pay attention to those unstable factors); 14. Correct; 15. Incorrect (no download tool is required); 16. Correct; 17. Incorrect (the information source is not absolutely reliable); 18. Correct; 19. Incorrect (the country has begun to pay attention to computer crime, even if there is no corresponding law).