First, a disclaimer of sorts, there are several places in the NWT that I strongly object to. Also, I am not with the WT, at all.
Next, translation from language to language is not a straight word for word type of activity. Some languages, at least one, cannot be translated directly into English. It would make little sense. When translating that language, it is absolutely necessary to insert many times the subject of the English sentence, even judging whether the subject is plural or singular - because in that other language, some things are said as if it is just understood who is speaking; thus, there is no need in that language to say it. (Very different)
So when you see the following: (just picked anything I could find)
NWT: Hebrews 1:10 . . .And: “You at [the] beginning, O Lord, laid the foundations of the earth itself, and the heavens are [the] works of your hands.
ASV: Hebrews 1:10 And, Thou, Lord, in the beginning didst lay the foundation of the earth, And the heavens are the works of thy hands:
You can see that the brackets of the NWT gives you a very accurate way of determining where the translator had to use his discretion to insert needed things into the English for it to not be a too rough, hard to read thing. The ASV and many other translations do not tell us where this has been done. Nonetheless, it was done.
