-----I called you yesterday evening, but you were not in.-----Sorry, I _____ in the shop with my mother.
I prefer________ sports shoes because they are very comfortable.
— I’m not sure you eat vegetables every day. — I know they are good for health, so I eat them every day.
The railway______ Qinghai to Tibet is the longest plateau (高原) railway in the world.
_____ of the twins has been there before.
You can _______the cake _______ten pieces.