British adventurer and swimmer Lewis Gordon Pugh became the first person to swim in the icy waters of North Pole，to raise awareness of how global warming ______ the polar ice cap.

A．had affected

B．is affecting

C．affected

D．will affect

刷手时，肥皂带入新洁尔灭溶液中，会导致（）

A.污染

B.沉淀

C.杀菌效力下降

D.变性

E.降低浓度