Nowadays people take___ exercise a day as they did in the past because of widely used automobiles.
| A．less than half | B．less than as half as |
| C．less than half as much | D．half less than |
She _____ the book sometime in the past as there is no way she could have answered the questions so accurately.
| A．ought to read | B．must have read |
| C．must read | D．should have read |
—Can I buy a Friday’s air ticket for Washington?
—I hate to say this, but there are no tickets ______ for Friday’s flight.
| A．precious | B．vacant |
| C．available | D．accessible |
Marie witnessed everything but it is amazing that she______ have said nothing about the murder.
| A．should | B．may | C．must | D．can |
I am looking forward to the time ______ I can work as a volunteer for the Youth Olympics .
| A．what | B．when | C．which | D．that |
_______ , sound and video can now be stored on a PC, on the Internet, or using some form of portable storage. Which one of the following is not suitable?
| A．As digital technology developing |
| B．As digital technology develops |
| C．With digital technology developing |
| D．With the development of digital technology |