Wind _______ electricity widely in many parts of the world.
| A．is used to produce | B．is used to producing |
| C．used to produce | D．used to producing |
22．Despite the fact that Betty is a lovely girl, she____be extremely difficult to work with sometimes.
| A．must | B．should | C．would | D．Can |
21．Have you heard_____report? People with______good knowledge of engineering are in great need in the job market.
| A．a; a | B．the; a | C．a; / | D．the;/ |
33. Generally speaking, ______ according to the directions, the drug has no side effect.
| A．when taking | B．when taken | C．when to take | D．when to be taken |
32. What the leader referred to in the report was really something _______.
| A．worthy to be considered | B．worth to be considered |
| C．worthy of considering | D．worth being considered |
31. After he retired from office, Rogers _______ painting for a while, but soon lost interest.
| A．saved up | B．took up | C．kept up | D．drew up |