MALE PROFESSOR: An-an-and if the two media have really different densities—like air and water—then most of the energy is gonna be reflected back; very little of it will keep going—uh, get transmitted into the new medium.

MALE PROFESSOR: I mean, just think how little noise from the outside world actually reaches you when your head's underwater.

http://ask.yygrammar.com/q-33714.html 之前已经问过类似的问题了，但是遇到下面实际问题，还有不敢确实How是引导感叹分句，还是引导疑问分句。

2. The only difference in this White House is how little influence the economists seem to have.

3. Parents who realize just how little difference hard work makes will work less hard.

请问老师，how little的用法和翻译？我的理解是类似于how much（多少），但是有时候可以强调很少。具体的用法，网上也没有找到。

第二个问题：第一个 how little是引导疑问分句，因为有just think这个逻辑。第二个第三个，没有疑问的语意，因此是引导感叹分句。