在西方经济发展的萧条期，消费需求的萎缩导致许多企业解雇职工甚至倒闭，在萧条期，被解雇的职工很难找到新的工作，这就增加了失业人数。萧条之后的复苏，是指消费需求的增加和社会投资能力的扩张，这种扩张要求增加劳动力。但是经历了萧条之后的企业主大都丧失了经商的自信，他们尽可能地推迟雇用新的职工。
上述断定如果为真，最能支持以下哪项结论?

A -2x²cosx⁴． B <img width="187" height="43" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222846_2105.jpg" /> C <img width="190" height="44" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222847_2886.jpg" /> D <img width="86" height="43" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222848_3199.jpg" />

A 0． B 1． C 2． D <img width="24" height="36" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222850_4292.jpg" />

A 充分必要条件． B 充分条件但非必要条件． C 必要条件但非充分条件． D 既非充分又非必要条件．

A 2x-2． B 2x+2． C x-1． D x+1．

A 1． B x²． C e^x． D 2x．

A 0． B <img width="23" height="41" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222854_6636.jpg" /> C 1． D <img width="24" height="41" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222855_7818.jpg" />

A <img width="24" height="41" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222857_8980.jpg" /> B <img width="24" height="41" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222858_8845.jpg" /> C <img width="23" height="41" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222900_0084.jpg" /> D <img width="23" height="41" src="https://www.beizhujiaoyu.com/uploads/202208/20211222222900_9917.jpg" />

A 1． B 2． C 3． D 4．

A 5． B 10． C 20． D 40．

A α₁必可由α₂，α₃，α₄线性表示． B α₂必可由α₁，α₃，α₄线性表示． C α₃必可由α₁，α₂，α₄线性表示． D α₄必可由α₁，α₂，α₃线性表示．