Economies of scale and limited investment choice will keep down charges .
规模经济和有限的投资选择会控制费用不会太高。
Arctic ice is considered vital for the planet as it reflects heat from the sun back into space helping keep down the planet 's temperatures .
北冰洋的冰层对我们地球至关重要，因为冰层可以将太阳的热量反射回宇宙，有助于降低地球的温度。
They try to keep down the cost of living .
他们努力压低生活费。
Keep down stay still .
保持低姿势不要动！
They couldn 't keep down their excitement .
他们抑制不住自己的激动情绪。
The kremlin says the move is part of the government 's attempt to keep down the prices of basic foodstuffs amid the country 's worst drought on record .