anesthetics
before effective anesthetics, surgery was very crude and very painful. before 1800, alcohol and opium had __success in easing pain during operations.laughing gas was used in 1844 in dentistry in the usa，but failed to ease all pain and patients __conscious.ether (useo
from 1846) made patients totally unconscious and lasted a long time.however, it could make patients cough during operations and sick afterwards.lt was highly flammable and was __in he**y glass bottles.chloroform (used from 1847) was very effective with few side effects.however, it was diffcult to get the dose right and could kill some people __the effect on their heart. an inhaler helped to regulate the dosage.
分析：
1.选项答案little
鸦片的意思就是鸦片，即酒精和鸦片在麻醉到来之前用来麻醉病人，正是因为它们作用不大，才会在前一句中出现粗暴而痛苦的修改。 很少是否定意义的积极形式，很少，意思是[[几乎没有]。 小和少都有这种用法，但因为成功是不可数的，所以选择小
调查技能]这种对语境理解的空洞检查。
在1800年之前，酒精和鸦片对缓解手术疼痛无效。
2.选项答案remained
顾名思义，笑气发明于1844年，但是没有办法缓解所有疼痛，病人还是清醒的。
调查技能]这种对语境理解的空洞检查。
笑气于1844年在美国牙科中使用，但它未能缓解所有疼痛，患者仍然保持清醒。
3.选项答案transported
解决问题的思路]前面已经有空了，只能被动地选择运输的桌子。
调查技术]这种空洞的语法检查。
它是高度易燃的，用沉重的玻璃瓶运输。
4.选项答案because of
解决的办法是正面和背面之间的因果关系：因为对他们心脏的影响，可能会杀死一些人
调查技能]这种对语境理解的空洞检查。
然而，很难获得正确的剂量，并且由于对心脏的影响，可能导致某些人死亡。
译本：
在有效麻醉剂出现之前，手术非常粗糙和痛苦。
before effective anesthetics, surgery was very crude and very painful.
在1800年之前，酒精和鸦片对缓解手术疼痛无效。
before 1800,alcohol and opium had little success in easing pain during operations.
笑气于1844年在美国牙科中使用，但它并没有缓解所有的疼痛，病人仍然保持清醒。
laughing gas was used in 1844 in dentistry in the usa. but failed to ease all pain and patients remained conscious.
乙醚（1846年开始使用）使患者完全失去知觉并持续了很长时间。
ether (used from 1846) made patients totally unconscious and lasted a long time.
但是，它可能会使患者在手术过程中咳嗽并在手术后生病。
however,it could make patients cough during operations and sick afterwards.
它是高度易燃的，用沉重的玻璃瓶运输。
it was highly flammable and was transported in he**y glass bottles.
氯仿（1847年开始使用）非常有效，几乎没有***
chloroform (used from 1847) was very effective with few side effects.
然而，很难获得正确的剂量，并且由于对心脏的影响，可能导致某些人死亡。
however,it was diffcult to get the dose right and could kill some people because of the effect on their heart.
吸入器有助于调节剂量。
an inhaler helped to regulate the dosage.