脉冲钨极氩弧焊电流幅值（即电流大小）按一定频率周期性变化，当为脉冲电流时工件上形成（），焊缝由许多焊点重叠而成。

[单选题]Questions 16 to 20 are based on the following passage. In a time of low academic achievement by children in the United States, many Americans are turning to Japan, a country of high academic achievement and economic success, for possible answers. However, the answers provided by Japanese preschools are not the ones Americans expected to find. In most Japanese preschools, surprisingly little emphasis is put on academic instruction. In one investigation, 300 Japanese and 210 American preschool teachers, child development specialists, and parents were asked about various aspects of early childhood education. Only 2 percent of the Japanese respondents (答问卷者) listed “to give children a good start academically” as one of their top three reasons for a society to have preschools. In contrast, over half the American respondents chose this as one of their top three choices. To prepare children for successful careers in first grade and beyond, Japanese schools do not teach reading, writing, and mathematics, but rather skills such as persistence, concentration, and the ability to function as a member of a group. The vast majority of young Japanese children are taught to read at home by their parents. In the recent comparison of Japanese and American preschool education, 91 percent of Japanese respondents chose providing children with a group experience as one of their top three reasons for a society to have preschools. Sixty-two percent of the more individually oriented (强调个性发展的) Americans listed group experience as one of their top three choices. An emphasis on the importance of the group seen in Japanese early childhood education continues into elementary school education. Like in America, there is diversity in Japanese early childhood education. Some Japanese kindergartens have specific aims, such as early musical training or potential development. In large cities, some kindergartens are attached to universities that have elementary and secondary schools. Some Japanese parents believe that if their young children attend a university-based program, it will increase the children’s chances of eventually being admitted to top-rated schools and universities. Several more progressive programs have introduced free play as a way out for the heavy intellectualizing in some Japanese kindergartens. Why do some Japanese parents send their children to university-based kindergartens?（）

[单选题]招标操作规范中的《招标文件编制规范》规定，对于一单一招的项目，保证金不超过项目估算金额的2%，且不超过（）。

[单选题]患者，女，53岁。患慢性支气管炎17年。近因受寒，咳喘加重，并见胸闷痰多，痰稀色白易咯出，舌苔白腻，脉滑。临床诊断为（　　）。

[单选题]关于橡胶类物品存放的注意事项，哪项是错误的（）

[单选题]中国文化的创始与奠基，指的是从远古至先秦这一漫长时期中的（）

[单选题]列车运行速度超过160km／h时，司机难以辨认地面信号，以司机为主的列车控制系统难以保证列车的安全运行，必须发展（）系统。

[单选题]男性，8岁。左大腿下段疼痛、肿胀1周。体温39．5℃，局部皮温高，深压痛，经抗感染治疗无效，局部穿刺抽出少量脓性液体。进一步治疗中，下列错误的是（）.

[多选题]预设条件： （1）额度模板A：上限20000、下限0、额度周期为日； （2）账户对1：申请了主动调拨服务，受控额度：模板A，影响额度：模板A； （3）无其他账户对选用额度模板A 某日，操作员对账户对1连续进行下列4次资金调拨，符合额度控制要求的包括（）。

[问答题]工程建设活动的起点是什么？

[填空题]机车车辆的牵引力、制动力均（）轮轨间的粘着力，否则会出现（）和（）的现象。

[填空题]脉冲钨极氩弧焊电流幅值（即电流大小）按一定频率周期性变化，当为脉冲电流时工件上形成（），焊缝由许多焊点重叠而成。

[填空题]脉冲钨极氩弧焊电流幅值（即电流大小）按一定频率周期性变化，当为脉冲电流时工件上形成（），焊缝由许多焊点重叠而成。

[填空题]脉冲氩弧焊通过对脉冲波形、脉冲电流、（）、两电流持续时间的调节和控制，可以准确改变和控制焊接参数、能量的大小，从而控制焊缝的尺寸和质量。

[填空题]氩弧焊分为（）氩弧焊和（）氩弧焊。

[判断题]氩弧焊主要包括钨极氩弧焊、熔化极氩弧焊。

[填空题]氩弧焊分为（）氩弧焊和（）氩弧焊两种。

[填空题]氩弧焊可分为（）极氩弧焊，与（）极氩弧焊。

[填空题]氩弧焊按所用电极不同可分为（）氩弧焊和（）氩弧焊。

[单选题]铝及铝合金采用手工钨极氩弧焊时，氩弧焊机电源应采用（）电源。

[判断题]紫铜管采用钨极氩弧焊时，氩弧焊机应采用直流正接。