下图所示地区为北半球，P、Q为某日晨昏线n与纬线m（80° N）的交点，经度差为120°。已知此时W（位于PWQ的中点）点的地方时为12时。据此完成下列问题。

此时下列说法正确的是（   ）

A．成都的昼长正在变长

B．成都日出时物影朝西南

C．我国东北地区的河流迎来当年第一次汛期

D．南极上空臭氧含量可能处于较低时期

Computers will become more advanced and they will also become easier to use. Improved speed recognition will make the operation of a computer easier. Virtual reality（虚拟现实）, the technology of(1)with a computer using all of the human senses, will also contribute to better human and computer(2). Other, exotic（奇异的）models of computation are being developed, including biological computing that uses living organisms, molecular computing that uses molecules with particular(3), and computing that uses DNA, the basic unit of heredity（遗传）, to store data and carry out operations. These are examples of possible future computational platforms that, so far, are limited in abilities or are strictly(4). Scientists investigate them because of the physical limitations of miniaturizing circuits embedded in silicon. There are also(5)related to heat generated by even the tiniest of transistors.

空白（4）处应选择（）

A.empirical

B.real

C.practical

D.theoretical