问题 选择题

把一个小铁球迅速压成一个铁饼,这时发生变化的物理量是它的(  )

A.内能

B.比热容

C.热量

D.质量

答案

把一个小铁球迅速压成一个铁饼,对铁球做功,使铁球的内能增加、温度升高;铁球的质量、比热容都不变;因没有说明铁球吸热或放热,不存在热量,

故选A.

单项选择题

Home prices slid in November, raising questions about whether the housing recovery is robust enough to maintain a sustained turnaround. From October to November, home prices fell 0.2% after (1) 0.1% in October, according to a report Tuesday by Standard & Poor’s/Case-Shiller’s home price index. (2) five of the 20 metro areas (3) by the index saw price increases for the month.

On a(n) (4) basis, prices were 5.3% lower in November than in November 2008. Prices were the same as in late 2003. "What we’ve seen (5) the past couple of months is that the pace of (6) has fallen down," says Maureen Maitland of Standard & Poor’s. "Some markets have (7) Is that because we haven’t (8) the foreclosure (回赎权的取消) cycle Because of unemployment We’re not seeing the (9) we were seeing in the last summer months. "

Metro areas that have seen a retreat in home prices (10) Seattle, Charlotte, Las Vegas and Tampa. All four (11) gains they made in recent months (12) . (13) , for the 20-metro index, the annual rate of decline is improving. That (14) , with other recent housing reports that show prices (15) or accelerating, could point to (16) the housing market is starting to (17) its footing, some economists say. Existing home sale prices were $178 300 in December, which is 1.5% higher than December 2008, according to a report this week by the National Association of Realtors. That was the first year-over-year (18) in median price since August 2007.

"The most (19) thing we can say is not only the market is stabilizing, but we’ve seen that housing demand is p," says Bernard Baumohl, with the Economic Outlook Group. "Housing probably will continue to climb upwards through the summer, (20) it could slip a little as the tax credit expires. \

14()

A.trend

B.circumstance

C.condition

D.hypothesis

单项选择题