21. The large passenger aircraft C919AC101, independently designed and developed by China, turned out to be a huge ______ success.

A. controversial     B. contradictory     C. commercial        D. compulsory

22. ---What do you think of Steven Hawking?

---Despite his disabled body, he was a man of scientific nature, _____worthy of admiration.

A. one             B. who            C. that              D. this    

23. The Internet gives people the chance to have the information they look forward ____to them  quickly and cheaply.

A. to deliver     B. to be delivered    C. to delivering        D. to delivered