Question 17: Ha Long Bay was first ________ as a World Heritage Site by UNESCO in 1994. A. recommended B. known C. suggested D. recognized Question 18: My uncle had a____________ of American coins and stamps. A. collect B. collective C. collection D. collector Question 19: He opened the door and let himself in quietly __________ not to wake the family. A. so as B. since C. so that D. because Question 20: This car really needs_______. Can you do it for me, son? A. being cleaned B. cleaning C. cleaned D. toclean