【简答题】听下面一段材料,回答第1-3题。 1. When did the speaker buy her ticket? A. Last Tuesday evening. B. At least two weeks ago. C. Last Monday morning. 2. How did the speaker go to the airport? A. By train. B. By car. C...
【单选题】SECTION C NEWS BROADCAST Directions: In this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. At the end of each news item, you will be given 10 ...
【简答题】300K 时某半导体导带底有效态密度1×10 19 cm -3 ,价带顶有效态密度5.6×10 19 cm -3 ,禁带宽度0.67eV(300K),0.76eV(77K): 计算电子和空穴状态密度有效质量。 计算77K时的本征载流子浓度及本征半导体费米能级位置。 在该半导体中掺入施主杂 质 1.3×10 18 cm -3 ,E C -E D =0.05eV,计算77K时的费米能级位置以及导带电子...
【单选题】SECTION C NEWS BROADCAST Directions: In this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. At the end of each news item, you will be given 10 ...
【单选题】Most interpreters agree that their really unsettling moments come when the speaker makes a joke involving an untranslatable-play on words. 'There is hardly anything people are more sensitive about tha...
【单选题】SECTION C NEWS BROADCAST Directions: In this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. At the end of each news item, you will be given 10 ...