网络操作系统的发展经历了从对等结构向 【9】 结构演变的过程。

袋底位于牙槽嵴根方的牙周袋为（）

A.龈袋

B.骨上袋

C.骨下袋

D.复合袋

E.复杂袋

Questions from 36 to 40 are based on the following passage:Against this background, the WTO faces several daunting challenges. The first is to continue bringing down tariffs on traded goods. Average penalties have fallen steadily since the GATT’s formation but even the most open economies retain lofty barriers: for instance, America still charges a tariff of 14.6% on import of clothing,five times higher than its average levy.Resistance to tariff cuts is pest in agriculture. According to Tim Josling,a trade expert at Stanford University, tariffs and other barriers on farm goodsaverage a crippling 40% worldwide and create distortions that “destroy huge amounts of value”. A new set of global farm talks is planned to start in 1999. At the least,you might think, these could lock in impressive reforms in Latin America and encourage further watering-down of the European Union’s Common Agricultural Policy.But they will prove difficult: squabbles over agriculture almost sank the Uruguay round.

According to the passage, which statement is NOT true（ ）

A．The WTO faces several daunting challenges, one of which is to continue bringing down tariffs on traded goods.

B．America still charges a tariff of 14.6% on import of clothing, four times higher than its average levy.

C．The pest resistance to tariff cuts is in agriculture field.

D．A trade expert said that tariffs and other barriers on farm goods averaged a crippling 40% worldwide.

循环水总磷要求控制在（）mg/L。

交流发电机的中性抽头的电压约为输出电压的（）倍。

A.0.5

B.1

C.2

D.3

软件开发环境是全面支持软件开发全过程的______集合。