Computers ____ in offices and homes since 1970s.
| A．have been used | B．had been used | C．was used | D．has been used |
The most successful retired athletes are those who can ____ the life skills they learned in sports to another area of life.
| A．contribute | B．employ | C．apply | D．arrange [ |
I like getting up very early in summer. The morning air is so good ____.
| A．to be breathed | B．to breathe | C．breathing | D．being breathed |
Some researchers believe that there is no doubt ____ a cure for AIDS will be found.
| A．which | B．what | C．that | D．whether |
______children whose parents had died in the earthquake ____ sent to live with families in other cities.
| A．A great number of; were | B．A great number of; was |
| C．The great number of; were | D．The great number of; was |
Much to our ______, John was finally persuaded to join in our travel to the South Pole.
| A．delighted | B．delighting | C．delight | D．delights |