（）are respectively the dominant transport mode in China and in the United States.
举一反三
- There are _____ states in the United States.
- The Constitution of the United States of America is the Supreme law of the United States.
- The two largest emitters of carbon dioxide are: A: China and the United States B: China and the United Kingdom C: Canada and the United States D: Mexico and the United States
- There are 50 stars on the national flag of the United States. They represent today's 50 States of the United States.
- Which countries reached an agreement at a United Nations conference A: The United States, China, India, Brazil and South Africa. B: The United States, China, Japan, Brazil and South Africa. C: The United States, China, India, New Zealand and South Africa. D: The United States, China, India, Brazil and Kore