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28.    We are going to do an (A. experiment / B. experience/ C. experiments) during Chemistry class now.

29.    It's not good to look at a computer (A. screen / B. scream/C. screens) for a long time.

30.    Today, many people on the planet have (A. access / B. exceed/ C. accesses) to the Internet

31.  He studies life in the sea. He is a marine (A. chemist / B. biologist/ C. chemistry)