As there is less and less coal and oil, scientists are exploring new ways of making use of ______ energy, such as sunlight, wind and water for power and fuel.
| A．primary | B．alternative | C．instant | D．unique |
．______was known to them all that William had broken his promise______ he would give each of them a gift.
| A．As, which | B．What, that | C．It , that | D．It , which |
．—When can we come to visit you?
—Anytime you feel like________.
| A．one | B．it | C．so | D．that |
Really great people always see the best in others; it is the little man who looks for the worst and finds_________.
| A．one | B．it | C．that | D．them |
．No one knows exactly when our ancestors started talking，but new evidence suggests _______might have happened a long time ago．
| A．which | B．what | C．it | D．they |
．—Do you think_____ worthwhile to go all the way to Los Angles to buy that computer?
—Well ,I’m going to visit some relatives, too.
| A．it | B．/ | C．this | D．that |