Exercise 1:
1.C. were (The sentence refers to a past situation.)
2D. artists’ (Possessive plural - the tricks belonging to the artists.)
3.A. pick (To pick something up means to lift it from the ground.)
4.C. unless (This introduces a condition: they can draw unless they cause an obstruction.)
5.D. crowd (A large gathering of people.)
Exercise 2:
1.C. of (Symptoms of a disease.)
2B. have (To have pains.)
3A. when (This indicates the time when headaches occur.)
4A. Medicine (Refers to treatment for the disease)
5B. lifestyles (Refers to general habits and ways of living.)
Exercise 4:
1.C. in 1958
2.D. Both A and B (Gary is located in the United States.)
3.B. 1964
4B. No, he didn’t
5.A. Michael Jackson
6.D. thirteen
7.A. twenty-six
8.A. Yes, it is
9.D. All are correct (Los Angeles is in California, which is in the U.S.)
Exercise 5:
1.B. over 30
2.D. It is about a rock musician
3.D. In 1998
4.B. He teaches them how to play in front of a real audience
5.C. Paul Green
Exercise 6:
1.are driving (Present continuous - an action happening now.)
2.went / saw (Past simple - completed actions in the past.)
3.finish (Present simple - refers to a future event after another is completed.)
4.weren't (Past simple of "to be" - negative form.)
5will write (Future simple - prediction about the future.)
6.doing (Preposition "in" is followed by the -ing form.)
7.to work (Volunteered to do something.)
8.eats (Present simple - habitual action.)
9.stewing (By + -ing form - describing how something is done.)
10.to drink (There is something to drink.)
11.provide (Modal verb "will" is followed by the base form of the verb.)