题目

Body language is a type of non-verbal communication, in which physical behavior   67   (use) to express information or feelings.   68  , different countries have different body languages. For example, not all countries have the same way of greeting when people meet. In Britain, people usually keep a certain distance and seldom touch strangers.   68   the contrary, in Spain, Italy or South American countries people approach others closer and arc more likely   69   (touch) them. In France, it is a typical custom   70   people kiss each other twice on   70   check w2．下列说法正确的是（　　）A．NaHSO4在熔融状态下的电离方程式为NaHSO4═Na++H++SO42-B．H2CO3是弱酸，故Na2CO3是弱电解质C．Fe3O4俗称铁红，常用作红色油漆和涂料D．2.4 g Mg无论与O2还是与N2完全反应转移的电子数均为0.2NA