The climate change conference has come to __________ end, but the developing countries are dissatisfied with __________ small step that the developed countries have taken to reduce the emission(排放) of water gases.

A．不填， a

B．不填， the

C．an , a

D．an, the

某太阳能热水器内装0.8m³的水．夏天天晴时，这个热水器接受阳光照射4h可使水温从20℃升高到65℃．在此过程中，水吸收的太阳能有多少J？相当于燃烧多少kg热值为3.36×10⁷J/kg的无烟煤？