小刚感冒了，没有及时治疗引起了中耳炎，病菌侵入中耳的通道是（　　）

阅读下面短文，掌握其大意，并根据所给字母的提示，写出一个英语单词的完整、正确形式，使短文通顺。

    More and more A____ are going to work by bike. Do you know why more people are riding bikes to work? We can answer the question in d____ ways. First, bikes don't need gasoline(汽油)，so it takes little m____ to use them. S____  a bike doesn't need much space, so it is e____ to find a place for it. And to ride a bike is good for one's h____ .People often d____ their cars to offices or to shops in the past. But now people think riding bikes is a good way of d____ sports. That's w____ more Americans are now riding to work by bike, and they are leaving（把...留下）their o____ cars at home.

从降水的时间分配来看，我国降水集中在____季节，相比之下，____季节雨水要少一些．

新制度的建立并非一帆风顺，获得各种政体的实验场称号的国家是（    ）