only在这句中为什么不倒装

如果only位于句子的开头,但它们作形容词用不是修饰介词短语或状语从句,而是修饰名词或代词则句子不需倒装：Only he managed to pass the exam. 只有他设法通过了考试.
“某些副词(短语)＋助动词＋主语＋谓语”的倒装结构
这些副词有(just)then, soon, often, only(in this way, then), so(＋形容词), especially, near(＋地点名词或短语), early(＋时间状语), in vain, many a time等等
1) So little about mathematics that the lecture was completely beyond me.
〔A〕 I know
〔B〕 I knew
〔C〕 do I know
〔D〕 did I know
2) a partial answer.
〔A〕 Will be found in this chapter
〔B〕 In this chapter found will be
〔C〕 In this chapter will be found
〔D〕 This chapter will be found in
3) So abundant and so prominent the material benefits of science are 〔A〕 that in the eyes of many 〔B〕 these seem to be the only 〔C〕 benefits which she brings 〔D〕 .