It would stay in place 19 you wanted it to.
答案：(C) as long as
【句型】as long as 字詞搭配「只要」，表示「只要你想要，它就會一直黏在原地」；despite that（儘管）、rather than（而不是）、no matter what（無論什麼，這裡是條件「只要」不是讓步）都不合。
as long as 你最熟的意思是「和……一樣長」，跟 as tall as、as far as 擺在同一組，所以看到它夾在兩個子句中間會愣一下，這一格答對率不到五成。as long as 除了比長度，更常見的用法是引導條件：只要……就……，意思等於 provided that（劍橋 English Grammar Today 的「As long as and so long as」條目）。
先讀語意：It would stay in place ___ you wanted it to.——「只要你要它待在那裡，它就會一直待在原地」，這是條件關係，不是讓步，也不是對比。再用句法驗算 no matter what：what 進到子句裡一定要當主詞或受詞，但 you wanted it to 的主詞是 you、受詞的位置由 it 占走了，沒有空位留給 what，句法上直接出局。順帶看句尾那個 to：後面的 stay in place 被省略了，這就是國中學過的 Would you like to join us?—I'd love to. 的 to，不是介系詞。
despite that 表讓步（儘管如此），可是本句前後並沒有互相衝突的兩件事。rather than 用來對比兩個對等的成分（tea rather than coffee），後面不接完整子句來表達條件。no matter what 除了上面說的句法問題，語意是「無論如何」，與「只要你要」的條件關係也不同。
as long as（只要，表條件）、so long as（只要，與 as long as 同義）、stay in place（留在原地不動）、hold sth in place（把某物固定住）、as far as I know（就我所知）、despite the fact that（儘管）
Art Fry was a researcher in the 3M Company. He was bothered by a small irritation every Sunday as he sang in the church choir. That is, after he 16 his pages in the hymn book with small bits of paper, the small pieces would invariably fall out all over the floor.
One day, an idea 17 Art Fry. He remembered a kind of glue developed by a colleague that everyone thought 18 a failure because it did not stick very well. He then coated the glue on a paper sample and found that it was not only a good bookmark, but it was great for writing notes. It would stay in place 19 you wanted it to. Then you could remove it 20 damage.
The resulting product was called the Post-it, one of 3M's most successful office products.