实名认证后发布多少件商品就可以申请免费开店？（）A.5件 B.8件 C.10件

放线菌生长时，对气体的要求是（）

A.专性需氧

B.专性厌氧

C.需加30％CO

D.微需氧或厌氧

E.兼性厌氧

精益管理的最重要内容就是努力消除什么现象？

下列关于混凝土的耐久性的相关表述中，正确的是（）。

A.抗渗等级是以28d龄期的标准试件，用标准试验方法进行试验，以每组八个试件，六个试件未出现渗水时，所能承受的最大静水压来确定

B.主要包括抗渗性、抗冻性、耐久性、抗碳化、抗碱一骨料反应等方面

C.抗冻等级是28d龄期的混凝土标准试件，在浸水饱和状态下，进行冻融循环试验，以抗压强度损失不超过20%，同时质量损失不超过10%时，所能承受的最大冻融循环次数来确定

D.当工程所处环境存在侵蚀介质时，对混凝土必须提出耐久性要求

The development of e-commerce may well bring the world into a brand new era of "electronic currency". At the moment, (52) areas in Europe, the United States and Asia have already started studying the possibility of an electronic currency. Electronic currency is not only about currency. It (53) to an entire finance system on the Net. It includes a virtual numeric currency, an electronic system of withdrawals, transfers and loans, and (54) cards of all shapes and sizes. The (55) of an electronic currency system implies the emergence of "virtual banks" and "virtual enterprises". Actually, the first virtual bank appeared in the US in 1995. (56) it is a small and insignificant bank, it represents the trend of the future. In time to come, we may even have to (57) the familiar paper currency.

As the Net pushes the economy (58) rapidly, the economy is also bringing the Net market forward, resulting in the Internet itself becoming the world’s largest emerging market. Of course, this is just the beginning. Although there are many companies which made huge profits (59) in the Internet market, they tend to be small companies. To date, most companies are making losses. The competition in the knowledge-based economy will also be more (60) This will definitely promote (61) and more efficient cooperation.

56().

A.If 

B.After 

C.Until 

D.Although

针叶林下多为酸性土壤，可适当施（）肥。

A.氮

B.磷

C.钾

D.钙