Could you please send _____ a doctor? My mom is ill.
---- Could you play ________ basketball when you were a primary school student? ---- No, I couldn't, but I could play ________ violin.
Keep an eye on my purse - I'm just going to the bathroom.
When the boy got his favourite bike, he was on top of the world.
If you buy ten bottles, the price of each bottle will come down to 5 yuan.
Be sure to give your family my regards.