Million、billion等大数字用法 — 英语词汇题
题目
根据句意和中文提示，用 million/billion 的正确形式补全句子：
1. The Yellow River is about 5,464 kilometres long, and about two ______ (百万) people live near it.
2. China has a population of over 1.4 ______ (十亿).
3. ______ (百万) of tourists visit the Great Wall every year.