She is always the first staff to go to the office and the last to leave，______ I guess is why she is promoted so quickly.
| A．who | B．which | C．that | D．what |
The singer, together with some of her fans, _____a song on the stage.
| A．sing | B．sang | C．is singing | D．are singing |
He is known _____ a scientist and famous _____ his research on rice.
| A．for; as | B．for; for | C．as; for | D．as; as |
．I live at a busy street and the loud noise nearly ____me mad.
| A．catches | B．buries | C．drives | D．influences |
There is no doubt _____ they will win the game.
| A．that | B．when | C．why | D．what |
______ he has gone abroad is not true.
| A．Whether | B．When | C．That | D．Why |