Not every winter is critical for deer of course. If the winter has light snow， survival and productivity next spring will be high. But if deep snows come and the weather remains cold for several weeks， then the deer must spend more energy to move about， food will be harder to find， and they must then depend more on their fat reserves to pull them through. If such conditions go on for too long some will die， and only the largest and strongest are likely to survive. That is a fundamental rule of life for wild， free wandering animal such as deer.

    Yes， life—and death， too —— is a cycle that goes round and round， and when animals die their bodies become food for other life forms to use by converting them into energy.

    And the cycle continues.

    Phrases & Expressions

    go round function smoothly

    in the form of以…形式

    in point appropriate； pertinent 适用的；相关的

    in （good） condition in good health， physically fit

    give birth （to）

    bear； （fig.） produce 生（孩）子，产（仔）；产生，引起

    draw on take or use as a source 利用；动用

    slow down（cause to ） go more slowly than usual； （cause to ） live， work， etc. in a less active and intense way （使）慢下来；（使）放松

    turn down reduce the force， speed， loudness， etc. of （sth.） by using controls 减弱；关小，调低

    move about travel around； go from one place to another

    pull through help （sb.） to survive a period of danger or crisis 使渡过危险或危机