The companies are working together to create they hope will be the best means of transport

问题补充：

The companies are working together to create they hope will be the best means of transport in the 21st century.

A. which

B. that

C. what

D. Who

答案：

A. which

B. that

(答案→)C. what

D. Who

解析：主要测试宾语从句。此题类同于（天津卷 15)的高考试题，具体解析可以参考上文。而且句子中存在一插入语they hope，可以采用先去掉的方法来解决。句子意思：所有公司一块工作目的在于创造出他们希望市二十一世纪最好的交通工具。