【单选题】What does a successful speaker require?
A.
The skills or hobbies that you are good at.
B.
Knowledge of both sources and the types supporting materials that speakers typically use.
C.
Talk about a subject with which you had some personal experience.
【判断题】A successful speaker can talk whatever he/she wants. _______.
【判断题】从宏观上看,所有的和田籽玉水中鹅卵石浑圆度很好。
【简答题】These are the key factors for being a successful speaker, and they are _____ my own experience.
【单选题】A successful speaker can talk whatever he/she wants. _______
【单选题】关于“热机”,下列说法中错误的是: [ ]
A.
.通过技术改进,可以使热机的效率达到100%
B.
.减少城市热岛效应的措施之一就是倡导“绿色出行”。
C.
.用水而不用其它循环物质降低热机的温度,主要是利 用水的比热容最大的特性 D.严寒的冬天,有人晚上把热机水箱中的水放出,是防止气温降低时,水凝固而胀坏水箱
【单选题】下列物质中热导率λ最大的是________。