30.The extra room________very useful when we had visitors.
I went back to the cinema to look for my keys, only __________.
The Chinese language differs from many Western languages ________it uses characters which have meanings and can stand alone as words.
It is often that human beings are naturally equipped to speak.
By the time she reached the corner of the street, the footsteps _________.
As Polly observed the passengers on the train, she _______that she was being watched by a tall man in a dark coat.