Thethieftookawaythewoman’swalletwithout________.
A、beingseenA
without 是介词，其后的动词必须用动名词形式。根据句意，此句需要用被动形式，所以答案是 A 。
This is an important problem _______ too few social scientists have researched.
The reply, when it finally came, was ________ the negative.
_______forthefreeticket,Iwouldnothavegonetoseefilmsooften.
If you are walking away from a clock tower ，you will hear the ticking of the clock fade to a point ________ it cannot be heard.
EmpiricalstudiesshowthattheprocessofSLAisaprocessofconstructingandmodifyingrulesofcommunication.
