— What do you think of the book?
— Oh, excellent. It is worth __________ second time.
| A．to read a | B．read a | C．reading a | D．being read a |
He is ____our teacher; he is also our best friend.
| A．less than | B．rather than | C．more than | D．better than |
--Why does the river smell terrible?
--Because large quantities of water__________.
| A．have polluted | B．is being polluted | C．has been polluted | D．have been polluted |
_______that they lost the game, tears came down Kate’s face.
| A．On hearing the news | B．When heard the news |
| C．The moment she heard the news | D．While hearing the news |
Children’s brains can’t develop properly_______ they lack protein(蛋白质).
| A．when | B．since | C．because | D．unless |
With all his attention ____ on the computer game, the boy even didn't notice his mother came in.
| A．was fixing | B．was fixed | C．fixing | D．fixed |