1 . _________ (在……之前) to this, scientific experiments did not show a definite link between mobile phone use and cancer.

2 . D___________ to her work, she rarely rests at weekends.

3 . The spokesman was seated in front of all the journalists at the press conference, _______ to answer all kinds of questions.

A．prepared	B．preparing
C．to be prepared	D．having prepared

4 . She says she pulled out of the campaign, _______ (恐惧）and angry. (根据汉语意思填空)