Question

It is our duty ______much attention to ________ our best to keep our city clean.

A．to pay, trying	B．paying, trying
C．pay, try	D．to pay, try

Answer 1

A

解析试题分析：句意: 注重尽我们最大努力保持我们的城市清洁是我们的责任。pay attention to是固定词组，注意……。try one’s best to do 尽力做，是固定词组。不定式to pay much attention to try our best to keep our city clean是句子的真正主语，代词it是形式主语。据句意，故选A。
考点：考查动词短语和非谓语动词。