21. After theythe first super computers in the 1940s, scientists and engineers began to develop ways to create networks.

A. create
B. created
C. have created
D. has created

22. Harvey finished his research paper, but he needed to check it before submitting it to the professor.

A. to type
B. typed
C. typing
D. type

23. We will inform you of the result the program is approved by the board.

A. in order that
B. as if
C. even though
D. as soon as

24. Having your smartphone or computer_ may cause a lot of trouble to you.

A. damaged
B. damage
C. damaging
D. to damage

25. Anyoneworks in the retail business needs to be good at calculating and communicating.

A. which
B. whom
C. who
D. what

31. Effective feedback is well timed so that the employee can (easy)connect the feed- back with his actions.

32. Today, as natural resources become scarcer and manufacturing costs rise, recycling is (important) than ever.

33. With the work (do), these scientists began to plan another research project.

34. For social robots to work successfully, they have to (accept)by humans.

35. The company has taken several steps to speed up the (move)of goods from the seller to the customer.