【单选题】You are____ to ask the teacher for permission if you want to leave the classroom.
【单选题】If you are physically weak, you are ______ to a bad cold.
【单选题】You are about to enter a compartment to investigate a suspected smoldering fire. If you are not wearing a self-contained breathing apparatus, you should test the compartment atmosphere to determine if...
【简答题】已知几个集成运放的参数如表 P4.3 所示,试分别说明它们各属于哪种类型的运放。 表 P4.3 特性指标 A od r id U IO I IO I IB - 3dB f H K CMR SR 单位增益带宽 单位 dB M Ω mv nA nA Hz dB V/ μ V MHz A 1 100 2 5 200 600 7 86 0.5 A 2 130 2 0.01 2 40 7 120 0.5 A...
【简答题】非正式的邀请,通常是以_______形式来表现的。正式的邀请,既讲究礼仪,又要设法使被邀请者备忘,故此它多采用______的形式,即邀请函的形式。