_______ for the free ticket, I would not have gone to see film so often.
A、IfitisnotC
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。Haditnotbeenforthefreeticket=Ifithadnotbeenforthefreeticket。
Bloomfielddrewon______psychologywhentryingtodefinethemeaningoflinguisticforms.
Younger children are curious ________ how things work ，and many of them want to take apart everything within their reach.
Thisisanimportantproblem_______toofewsocialscientistshaveresearched.
Hetalkedalotaboutthingsandpersons________theyrememberedintheschool.
Childrenhaveanatural________abouttheworldaroundthem.
