Peter must be ill.It's the only thing that can ________ his strange behavior.
Is this the reason _____ in the report for her success in the job ?
The extra room _______ very useful when we had visitors.
I ‘ ll help you_________.
Hello, I _______ you ______ in London. How long have you been here?
She is the only one among the _______ writers who ______ stories for children.