(2013·东北三校4月联考)—Car prices have been going down sharply in the last 20 years.

—It's not surprising because the law of market ________ the price of a product.

A．is controlling

B．controls

C．has controlled

D．controlled

不可能出现的体征为

A．移动性浊音阳性

B．液波震颤

C．蛙腹

D．蜘蛛痣、肝掌

E．胃肠型和蠕动波