已知x=0.5，那么2x与x2的大小关系是（ ） A．2x大 B．x2大 C．相等

中央银行只与商业银行等金融机构发生业务往来，而不直接面向企业单位和个人经办金融业务，这一职能具体表现不正确的是( )。

A．集中存款准备金，商业银行等金融机构必须按规定比例将部分存款交存中央银行，形成存款准备金
B．最终贷款人，在商业银行等金融机构周转资金不足时，中央银行以再贴现、再抵押或直接贷款等形式，向这些金融机构提供资金支持，从而成为”最终贷款人”
C．集中利息，商业银行等金融机构必须按规定比例将部分存款交存中央银行，形成利息准备金
D．组织商业银行等金融机构间的清算，由于各商业银行等金融机构在中央银行开立存款账户，并保留一定数额的准备金

政府贷款一般利率较高，利率浮动，风险较大。

在天津领取失业金需满足什么条件？一般最长能领取多久？每月多少钱？

采用双倍余额递减法计算折旧时，其正常折旧率( )。

A．逐年降低
B．逐年提高
C．各年相等
D．前几年提高，后几年降低

The Theory of Continental Drift has had a long and turbulent history since it was first proposed by Alfred Wegener in 1910. (46) Vigorously challenged yet widely ignored, the theory had languished for half a century, primarily due to its lack of a plausible mechanism to support the proposed drift. With the discovery of sea-floor spreading in the late 1950’s and early 60’s, the idea was reinvigorated. Plate tectonics is now almost universally accepted. Many details of the mechanism are to be worked out.

The surface of the Earth is divided into approximately six large plates, plus a number of smaller ones. The plates are’ bounded by an interconnected network of ridges, transform faults, and trenches. Ridges, also called spreading centers, occur where two plates are moving away from each Other. As the plates separate, hot molten mantle material flows up to fill the void. (47) The increased heat resulting from this flow reduces the density of the plates, causing them to float higher, thus elevating the boundaries by many thousands of feet above the colder surrounding sea floor. (48) Ridges on the ocean floor form the longest continuous ranges of mountains on the planet, but. only in a very few places on the Earth do these mountains rise above the ocean surface.

New sea floor is constantly being created along spreading centers. Obviously somewhere else old sea floor must be going away. This occurs in trenches, also called subduction zones. Trenches occur along the boundary between two plates that are moving towards each other. (49) Where this occurs, one plate is bent downwards at about a 400 angle and plunges under the other plate’s leading edge, eventually to melt back into the liquid mantle below. As the subducting plate is heated back up to mantle temperatures, certain minerals in the plate melt sooner than others. (50) Minerals that melt at lower temperatures and are lighter than the surrounding material tend to rise, melting their way up through the overriding plate to erupt as volcanoes on the ocean floor. As these volcanoes grow, they rise above the ocean surface to form lines of islands along the leading edge of the overriding plate. Numerous islands of Micronesia and Melanesia in the western Pacific were created in this way.

(49) Where this occurs, one plate is bent downwards at about a 400 angle and plunges under the other plate’s leading edge, eventually to melt back into the liquid mantle below