发酵粉是糕点的常见膨松剂，成分一般是NH₄HCO₃、NaHCO₃，某同学将发酵粉加入到一定量的氢氧化钙饱和溶液中，产生大量气泡和白色固体，溶液呈无色．

Ⅰ、为确定气体和固体及溶液的成分，该同学进行了如下的探究：

    The Yellow Mountain is one of the most famous m____  in China. Every year l____  of Chinese people and foreigners visit it. It is not f____  from here. You can s____ about two hours getting there by bus. You can also go there by train o____  by plane. When you are c____ the mountains, you can e____  the sea of clouds, wonderful trees and rocks (岩石) a____ you. In the e____ morning when the sun rises (升起)，the sun looks b____ . It is really a good place to go.

五四运动促使北洋政府拒绝在“对德和约”上签字。“对德和约”指的是（   ）