【单选题】精车时,为了保证台阶平面与工件轴线的垂直,车刀装夹时实际主偏角应______90°。
【简答题】热虹吸管(又称重力热管)是一种封闭、竖直放置的容器,其沸腾段吸收的热量在其冷凝段放出,如附图所示。今用抛光的不锈钢制成一热虹吸管,d=20mm、l b =20mm,l c =40mm,l i =40mm。设1.013xl0 5 Pa压力下的饱和水在沸腾段沸腾.热流密度q是临界热流值的30%。 求沸腾段的平均壁温t wb
【单选题】A greater number of newspapers are sold in Town S than in Town T. Therefore, the citizens of Town S are better informed about major world events than are the citizens of Town T. Each of the following,...
A.
Town S has a larger population than Town T.
B.
Most citizens of Town T work in Town S and buy their newspapers there.
C.
The average citizen of Town S spends less time reading newspapers than does the average citizen of Town T.
D.
A weekly newspaper restricted to the coverage of local events is published in Town S.
E.
The average newsstand price of newspapers sold in Town S is lower than the average price of newspapers sold in Town T.
【单选题】关于软件测试的目的,下列说法错误的是()。
B.
一个好的测试用例在于能够发现至今未发现的错误。
C.
一个成功的测试是发现了至今未发现的错误的测试。
D.
测试的目标是以最少的时间和人力改正软件中潜在的各种错误和缺陷。
【单选题】出现下列哪个情况,最有利于区分精神分裂症和安非他明中毒所致精神病性症状 ( )
【单选题】The town relies on the ___ tourist industry for jobs.
【单选题】水平仪可用于测量机件相互位置的 ( )误差。
【单选题】下列关于玉米种子的说法中,正确的是 ①玉米种子的胚由胚芽、胚轴、胚根、子叶四个部分组成 ②胚是种子的主要部分,是新植物体的幼体 ③将一粒玉米种子纵切后,在切面滴碘液,整个切面都变得一样蓝 ④种子中的子叶发育为叶,胚芽发育为芽,胚轴发育为茎,胚根发育为根
【判断题】( T )水平仪可用于测量机件相互位置的平行度误差。