介词without的用法比较多样,下面学习啦小编为大家归纳相关的用法:<br>一、without的基本用法<br>1.(用在no,not,never等否定副词之后,强调肯定)没有……不,没有……则不能……,每……必定…….如:<br>You can't get rich without taking risks.人不冒险不富.<br>The old man cannot walk without a stick.那位老先生离开手杖就走不了路.<br>Don't go out without a coat:you'll catch your death.别不穿外套出去,会得重感冒的.<br>2.(表否定)没有,无,不需.如:<br>The letter was posted without a stamp.那封信没贴邮票就寄出去了.<br>We got there without any trouble.我们到了那儿,一路上没遇到任何麻烦.<br>You'll get wet if you go out in the rain without an umbrella.雨天外出不带伞会淋湿的.<br>3.(表条件)若无,若非.如:<br>I don't like to go to a country without knowing something of the language.我要是不懂得一点那个国家的语言,就不想到那个国家去.<br>Without water,we cannot live.没有水,我们就活不了.<br>Can you see without your glasses?你不戴眼镜能看得清东西吗?<br>4.(与-ing形式连用)不,无,没.如:<br>She entered the room without knocking.她没敲门就进了房间.<br>They had to stand for hours without changing position.他们得一动不动地站几个小时.<br>It wasn't very polite of you to serve yourself without asking.你也不问一声就自己吃起来是不太礼貌的.<br>二、without作表语的用法<br>without引出的介词短语通常用作状语,但有时
心脏支架手术后血压低的原因如下:1、急性期,即支架手术1-2日内血压低,需高度重视,患者是否出现并发症,如心包填塞、血管穿孔等引起血压偏低,或血管急性闭塞引起心肌梗死,导致血压偏低。需积极寻找血压低的原因并及时处理,此种血压低可能是致命性疾病的危险信号;2、部分患者经支架手术后数周或数月出现血压低的表现,通常与支架手术无较大关系,可考虑药物或最近饮食等其它方面的原因,导致血容量少,引起低血压。