Don’t answer the phone when the cell phone is being charged, for it ________ be very dangerous sometimes.
If it _____, we will go to visit the zoo.
Our English teacher _____ all the exercise books last Friday evening.
The bus came after I _____ for about half an hour.
I saw that he _____ at seven o’clock last night.
I didn’t go to see the film because I _____ it.