To be blunt about the subject, if a bottle of oil does not contain the following basic information then DO NOT buy it look for something that does! 1  The purpose for which it is intended (i.e. 2  Motor oil, Gear oil etc). 3  The viscosity (i.e. 10w-40, 5w-30 etc for Motor oils and 80w-90, 75w-90 etc for Gear oils).
The definition of an incursion is an invasion, or the act of entering into an activity or place. 1  An example of an incursion is a military brigade entering enemy territory. 2  An example of an incursion is taking an art class to get a little experience into painting.
Recursion is a function that calls itself. How to use it, when to use it and how to avoid bad design are important to know, which requires you to try it out for yourself, and understand what happens. The most important thing you need to know is to be very careful to not get a loop that never ends.