Physical activity is an important factor in maintaining fitness.

体育活动是保持健康的一个重要因素。

The relatively cheap price of food may be a contributing factor to the increasing number of overweight people.

相对便宜的食品价格可能是引起超重人数不断增加的因素之一。

The cost of butter quadrupled and bread prices increased by a factor of five.

黄油的价格是原来的4倍，面包的价格上涨了5倍。

A sunscreen with a protection factor of 30 allows you to stay in the sun without burning.

一种防护系数为30的防晒霜使你能够待在太阳底下而不被晒伤。

You'd better consider this and factor this into your decision making.

你最好考虑这一因素并在决策时将其包括进来。