The Granville Sharp Greek Rule sates:
If two words are separated by kai and each are preceded by a word for "the," eg. o or h, then the two words refer to the same thing.

For example in Revelation 12:9 we have "the devil and Satan" in this form:
o kaloumenoV DiaboloV kai ¢o SatanaV
So we see that the words devil and Satan refer to the same person.

However; in Mark 1:29 we have "James and John" in this form:
Iakwbou kai Iwannou
So James and John must be two different people. 

The following are passages where the Granville Sharp Rule helps in understanding various doctrines.

Calvinists try to say in Ephesians 1:11 the "council and will" refer to the same thing. this would aid them in saying foreknowledge is predestining people not just knowing the future. but the Greek has:
thn boulhn tou qelhmatoV autou
So we see that council and will are two different things.
And in Acts 2:23 the "definite plan and foreknowledge of God" is:
th wrismenh boulh kai prognwsei tou qeou
The tou qeou, or "of the God" is just a title. Notice "the council" and just "foreknowledge."  So again we see that council and foreknowledge are two different things.

In 1 Corinthians 14:15 the "pray with my mind and my spirit also" is:
proseuxomai tw pneumati, proseuxomai de kai tw noi. 
Both sets of nouns are in singular dative form. (Ends in i ) 
Since Granville Sharp Rule applies here, praying with your mind and spirit at the same time means the term "praying in the Spirit" does not always mean praying in tongues.

Greek version is the (NA26) Nestle Aland 26th Edition Greek New Testament.