— What made Bill so angry?
— ______. His girl friend promised to come at 8:30, but she hasn’t come yet.
| A．Having kept waiting | B．Being kept waiting |
| C．To be keeping wait | D．Being kept waited |
--- We expected you yesterday．
--- I'm sorry, Iyou to say that I couldn't be here until today．
| A．must have called | B．would be calling |
| C．could have been calling | D．should have called |
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 |