跨文化沟通具有下列哪些特征（）。 A.是一个比较普遍的现象 B.仅仅发生在与外国人面

对于实数a，b，现有四个命题：①若a＞b，则a²＞b²；②若a＞b，则a-b＞0；③若a＞|b|，则a²＞b²；④若a＜b＜0，则a²＞b²；其中，真命题的个数是（　　）

A．1个

B．2个

C．3个

D．4个

下列有关细胞器的说法正确的是[ ]

A．核糖体是噬菌体、细菌、酵母菌唯一共有的细胞器

B．线粒体是有氧呼吸的主要场所，在其中生成的产物有丙酮酸、二氧化碳和水

C．中心体是动物细胞才具有的细胞器，与细胞的有丝分裂有关

D．在成人心肌细胞中线粒体的数量显著多于腹肌细胞中的线粒体

芳胺类药物中可直接发生重氮化反应的是

A．苯佐卡因，普鲁卡因

B．普鲁卡因胺

C．利多卡因

D．对乙酰氨基酚

E．A+B

按机车大修规程要求：制动软管接头、连接器有裂纹需更换，制动软管连接器须以0.6Mpa的压缩空气在水槽内试验，保持5min不许泄漏，外直径膨胀不许超过（）

Although Damon had ample time earlier in the month to complete the paper he is scheduled to present at a professional conference tomorrow morning, he repeatedly put off doing it. Damon could still get the paper ready in time, but only if he works on it all evening without interruption. However, his seven-year-old daughter’s tap-dance recital takes place this evening, and Damon had promised both to attend and to take his daughter and her friends out for ice cream afterward.
Thus, because of his procrastination, Damon will be forced to choose between his professional and his family responsibilities. The argument proceeds by______.

A．providing evidence that one event will occur in order to establish that an alternative event cannot occur

B．showing that two situations are similar in order to justify the claim that someone with certain responsibilities in the first situation has similar responsibilities in the second situation

C．invoking sympathy for someone who finds himself in a dilemma in order to excuse that person’s failure to meet all of his responsibilities

D．making clear the extent to which someone’s actions resulted in harm to others in order to support the claim that those actions were irresponsible

E．(E) demonstrating that two situations cannot both occur by showing that something necessary for one of those situations is incompatible with something necessary for the other situations