He thought that painting copied by a modern artist was ______ great value and bought it ____ over a thousand dollars.

A．at; for

B．of; for

C．of; at

D．for; by

作为发展中国家，我国在（）第一期行动中不承担减排义务，但作为目前的温室气体排放大国之一，随着经济发展和人口增加，我国将面临越来越大的减排压力。