He thought that as he had worked for the company for so long, he     higher pay.

A．received

B．required

C．deserved

D．saved

大量氮、磷等植物性营养元素进入水体后，藻类大量繁殖，水质恶化，水生生物死亡，一般称为（）。

A、富营养化

B、湖泊酸化

C、湖泊氧化

D、重金属物质污染