like most herbivores, will maximize their net rate of energy intake per unit time. In order to maximize energy, beavers will choose trees that are closest to their central place (the water) and require the least retrieval cost. Since beavers are trying to maximize energy, we
hypothesized that they will tend to select some species of trees over others on the basis of nutritional value.
Methods
这部分通常包括Material 和 Procedure两个部分。
Material：
详细的写出实验用到的材料，设备，器材。像下面这样是不够详尽的： Chromatography
Light bulbs
Computer
比较一下下面的：
LC-10AVP Plus High-performance liquid chromatography
24 incandescent 60W light bulbs arranged in a 6*4 rectangular matrix (See Figure 2)
Dell Precision T7500 (Xeon X5550 2.66GHz, 6GB RAM, 64 bit Windows 7 Professional)
另外，如果实验对象中有人的话，介绍人数，群体背景。用Subjects 来称呼。比如
Subjects
We tested 150 third-grade students chosen at random from a pool of 346 applicants from eight London public and private elementary schools. the students represented a fairly wide range of economic backgrounds. all agreed to participate in our study in exchange for a 25 pounds gift certificate from a local toy store.
Procedure
详细写出每一步步骤。 不要虚构理想化实验， 不要夸大某个过程
如实叙述即可。如果步骤比较多就用数字标出每一步。
example:
The test performed on the potentiometer was accomplished by winding a string around the potentiometer shaft, attaching a mass to the string, and letting the mass fall. The change in resistance of the potentiometer with time indicated the acceleration of the mass. In this experiment it was assumed that the constant Coulomb friction torque was the only friction affecting the potentiometer. If this assumption were true, the friction force from the torque would be Ff = T/r (where T is the torque and r is the radius of the potentiometer’s shaft). Likewise, the gravity force would be Fg = mg (where m is the mass tied to the string and g is the gravitational acceleration). A force balance then gives