自来水厂把河水变成生活用水时，需要经过消毒杀菌，下列能作为消毒剂的是（　　）

A．氯气

B．石灰水

C．明矾

D．生理盐水

The artist spent years on his monumental painting, which covered the whole roof of the church, the biggest in the country.

A．archaic

B．sentimental

C．outstanding

D．entire