Exercise 1. Mark the letter A, B, C, or D to indicate the correct to each of the following questions. Các bạn chỉ cần ghi đáp án và dấu hiệu nhận biết 6. 3-D printing ____ complex tools and components. A. is used for produce B. is used to produce C. uses for producing D. uses to produce 7. She was old enough ____ up her own mind. A. made B. make C. making D. to make 8. My computer is used for ____ music and video. A. having played B. play C. playing D. to play 9. My father uses a calculator to ____. A. be calculated B. being calculated C. calculate D. calculating 10. Facebook is used ____ among the young. A. communicate B. communicating C. to communicate D. to communicating 11. Mary often watches YouTube videos to study how ____ a dish or make a cake. A. cook B. cooking C. to cook D. to cooking 12. We can use USB ____ information. A. for being store B. for store C. to store D. to storing