A body can only be observed at lower transit when（）.

A .  Set the body content type to JSP in the TLD B .  Scriptlet code is NOT legal in the body of st：simple C .  Add scripting-enabled= “true” to the start tag for the st：simple element D .  Add a pass-through Classic tag with a body content type of JSP to the body of st：simple， and      place the scriptlet code in the body of that tag.

A .  48 Ethernet 10/100 ports B .  Fast Ethernet and Gigabit Ethernet connectivity C .  dual-purpose copper or fiber uplinks D .  standalone fixed-configuration Layer 2 switching

A . changing the angle of the tilting plate B . changing the speed of the pump C . moving the slide block and rotor D . moving the shaft trunnion block

A . 正确 B . 错误

A .  private B .  no modifier C .  public D .  protected

A . on the prime vertical B . on the celestial horizon C . at lower transit D . on the Greenwich meridia

A . Ⅰonly B . Ⅱonly C . eitherⅠorⅡ D . neitherⅠnor

A . Mark the method with the keyword public. B . Mark the method with the keyword protected. C . Mark the method with the keyword private. D . Mark the method with the keyword package. E . Do not mark the method with any accessibility modifiers.

A . CCS B . the Customs C . MOC D . MSA

(30) A．A diet with meat only is not enough for our body. B．A diet with vegetables can sometimes be very costly. C．Meatless meals are equally nutritious and less expensive. D．Meatless meals cannot provide all the essential nutrients.

A．Right B．Wrong C．Not mentioned

A、If B、All that C、What D、If what

In practice, what often happens is that a new theory is devised that is really an extension of the previous theory. For example, very accurate observations of the planet Mercury revealed a small difference between its motion and the predictions of Newton's theory of gravity. Einstein's general theory of relativity predicted a slightly different motion from Newton's theory. The fact that Einstein's predictions matched what was seen, while Newton's did not, was one of the crucial confirmations of the new theory. However, we still use Newton's theory for all practical purposes because the difference between its predictions and those of general relativity is very small in the situations that we normally deal with. (Newton's theory also. has the great advantage that it is much simpler to work with than Einstein's ! ) It turns out to be very difficult to devise a theory to describe the universe all in one go. Instead, we break the problem up into bits and invent a number of partial theories. Each of these partial theories describes and predicts a certain limited class of observations, neglecting the effects of other quantities, or representing them by simple sets of numbers. It may be that this approach is completely wrong. If everything in the universe depends on everything else in a fundamental way, it might be impossible to get close to a full solution by investigating parts of the problem in isolation. Nevertheless, it is certainly the way that we have made progress in the past. The classic example again is the Newtonian theory of gravity, which tells us that the gravitational force between two bodies depends only on one number associated with each body, its mass, but is otherwise independent of what the bodies are made of. Thus one does not need to have a theory of the structure and constitution of the sun and the planets in order to calculate their orbits: Today scientists describe the universe in terms of two basic partial theories-the general theory of relativity and quantum mechanics. They are the great intellectual achievements of the first half of this century. Unfortunately, however, these two theories are known to be inconsistent with each other-they cannot both be correct. One of the major endeavours in physics today, is the search for a new theory that will incorporate them both-a quantum theory of gravity. We do not yet have such a theory, and we may still be long way from having one, but we do already know many of the properties that it must have. According to the passage, why can't any physical theory be permanently established？ A．Such a theory is only suggested as a possible way of explaining an idea. B．The person proposing such a theory may be incompetent. C．Observations always disagree with predictions. D．Observations are always falsified by predictions.

是 否