______ Kathy was watching TV, her mother asked her to go shopping.
---How long did it _____ you to work out the difficult maths problems? ---I ______ about half an hour on it .
It is very _______ of you to speak in front of all those people .
---Do you often play computer games? ---No, And neither do ________ of my classmates, you know we are very busy
I don’t know _____ or not he will come . _______ he comes , I will call you .
The robot needs _______ once a month. And we will check it for you for free.