Section A (15 marks)
Directions: For each of the following unfinished sentences there are four choices marked A, B, C and D. Choose the one that best completes the sentence.
21. Jane had just finished her homework ________ her mom asked her to practice playing the violin yesterday.
A. when B. while C. after D. before
22. Research shows that teenagers ________ talk about their day with family members at the dinner table are less likely to engage in high-risk behavior.
A. what B. who C. whom D.\
23. ________ their heavy load, the two brothers walked along the river bank.
A. Carrying B. Carried C. To carry D. Carry
24. The boys followed the marks that they ________, until finally they found their way back to the campsite.
A. left B. have left C. had left D. have been left
