..---Who ________ it be that is knocking at the door?---It________ be Mother, but I’m not sure.
As far as I know, this man ____ risk anything than lose the ring for his wife.
She locked her room _____ a thief would break into it.
She said she would spend her holiday ___ Beijing.
Whenever I go to Beijing, ____ is quite frequent, I will go to visit the Great Wall.
They told us that these small apples are often sweeter than big ____.