"Society" is a(n)              term;it may mean much or nothing.

autonomous

ambiguous

fragrant

fragile

考查形容词词义辨析。句意：“社会”是一个模棱两可的词；它可能意味着很多，也可能没有意义。autonmous 自治的；ambiguous模棱两可的；fragrant芳香的；fragile脆弱的。结合后文it may mean much or nothing可知，空格处填ambiguous模棱两可的。故选B项。

It was along the Mississippi River _________ Mark Twain spent much of his childhood.

how

which

that

where

此处构成It was...that...强调句式，句中强调了介词短语along the Mississippi River。故选C。

Only when he returned ________ that the war had ended and the army had come back.

we tell

we told

did we tell

were we told

考查倒装句型。Only放在句首时，句子要用倒装语序；根据句意“我们被告知”可知，此处要用were we told。故答案选D。

--What is happening in that new area?

---New houses          over there.

are built

are building

have built

are being built

考查时态和语态。句意：在那个新区域里发生什么事情了？那儿建起来许多新的大楼。根据第一句时态is happening 可知，时态用现在进行时，故第二句也要用现在进行时，主语 houses与build 建立之间是被动关系，故用现在进行时的被动语态（am/is/are being done），此处为are being built，故选D项。