It is ___ the customers’ needs that has made chain stores so popular in big cities in China.
_____ according to the instructions, the robot can behave like a human being with average IQ.
The door _____ open, no matter how hard she pushes.
When I first met Doris I didn’t like her, but I ______ my mind.
An air crash accident happened to the plane, ______.
I wondered what difficulty he had _____ the plan.