In relation to breach of contract, explain two situations in which the innocent party can choose to terminate the contract, in addition to suing for damages. (10 marks)

以下哪种方法的出现解决了麻醉中呼吸道的管理问题（）

A.对乙醚全麻征象的判断

B.气管内插管

C.硬膜外麻醉的阻滞作用

D.硫喷妥纳临床使用

E.钠石灰用于二氧化碳的吸收