根据句子意思, 首字母和汉语注释, 写出适当单词。
（1）、Things are going f. （事事顺利）
（2）、When you travel in a foreign country, you can also learn its (文化).
（3）、The(主要的) idea of the article is to tell us how to save and protect water.
（4）、The Great Wall is one of the s of the world.
