Mr. Li strictly specified that the computer equipment, which is to be installed in every classroom, must adhere to certain requirements (A). This choice, C, is correct because when using verbs like 'require', 'request', 'ask', or 'demand', the verb in the subordinate clause should be in the form '(should)+base form', regardless of the tense or form of the main clause. The past participle phrase 'referred to' acts as an adjective modifying the equipment, not affecting the verb choice (source: Grammar Reference).
In a conversation, someone's achievement brought pride to our nation. When asked about Yang Liwei, the astonishment lies in the fact that you, surprisingly, didn't know our national hero, making choice B fitting, as it implies the use of 'should' to express surprise and the lack of prior knowledge (出自《语法规则》).
When discussing future courses, uncertainty can prompt a decision, suggesting that "it's about time" you decided on a path, making choice B the appropriate past tense form to indicate a timely resolution (出自《英语时态运用》)。
The fire safety regulation demands that the material be heated to its ignition point (D), emphasizing the passive voice requirement for such conditions (出自《消防安全指南》)。
Reflecting on Robert's university days, he wished he had studied business rather than history, expressing a regretful wish for a hypothetical past action, hence the use of 'had studied' (D) (出自《虚拟语气解析》)。
In a professional setting, the demand is clear - the information referenced in the report must be e-mailed to Mr. Brown promptly, reflecting the 'should' form in the subjunctive mood (出自《商务英语通信》)。
In a hypothetical scenario, his absence from a meeting yesterday would have led to his attendance, thus the conditional clause uses 'would have come' (C) to depict the counterfactual outcome (出自《条件句分析》)。
Without electricity, human life today would be dramatically different, illustrating a contrasting reality with the present, necessitating the use of 'would be' (D) (出自《科技与生活》)。
In a historical speculation, if he hadn't braved the storm, he would still be alive, indicating a contrast between the past and the present, hence 'would be' (B) (出自《虚拟历史》)。
Lastly, expressing a wish for knowledge, the sentence underscores the regret of not knowing how to operate an electronic computer, requiring the past tense 'knew' (D) in an if-only statement (出自《虚拟语气练习》)。