The condenser behind the refrigerator must keep clean because dust will affect the cooling rate.

柜后的凝结器则要经常清扫，因积在上面的尘埃会妨碍散热。

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The residents, for their part, realized that as landlords, they must keep the neighborhood clean in order to obtain the highest rents from their commercial tenants.

FORBES: Social REITS To Re-house Slums & Regenerate Cities

As long as countries like China keep going all in on clean energy, so must we.

WHITEHOUSE: State of the Union 2013

As long as countries like China keep going all-in on clean energy, so must we.

FORBES: Full Text: President Obama's 2013 State Of The Union Address