_______forthefreeticket,Iwouldnothavegonetoseefilmsooften.
C
从本题后半句可以看出这是一个与过去事实相反的虚拟条件句， 从句中的动词要用 “had +过去分词”，如果将 if 省略，had 要位于主语之前，构成倒装句， 故本题的答案是 C。Had it not been for the free ticket =If it had not been for the free ticket 。
Thisisanimportantproblem_______toofewsocialscientistshaveresearched.
A linguistic theory is constructed about what ______ is and how it works.
______ moves on a scale of the national language, dialects, and individual ways of communication.
Country life is better than city life ________ it offers fresh air and noiseless environment