Dunhuang used to be a marketplace _____everybody came and were able to purchase silk, tea, porcelain(瓷器)…
If there were no examinations, we should have_____at school.
She is_____new comer to____chemistry but she has already made some important discoveries.
Shortly after the accident, two___police were sent to the spot to keep order.
These tables and desks are all made of_____.
Jumping out of_____airplane at ten thousand feet is quite_____exciting experience.