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“which of the two” and “either of the two” are singular noun phrases, so you use the singular verb “contributes.” There are two things, but the word “which” refers to ONE of the two things (EITHER of them), so it is singular in this case and therefore takes a singular verb.
“away” means “not here,” and “far away” means something like “in a distant point not here.” It is normally used to indicate places and physical distance, as in Point X is far away from point Y. It is more common to use “far from,” not “far away from,” to indicate unlikeness and difference in character, so we would normally say He is far from a conservative as opposed to He is far away from a conservative.
No, “after” almost always indicates a simple past or simple present tense. Words like “after” and “before” that create simple designations of time indicate a simple tense. For example, we would normally say *After I ate breakfast, I went to school<a href=“simple%20past%20tense”>/i</a>, not After I had eaten breakfast, I went to school, because “I had eaten” is not really an event (it is the STATE of having eaten); since it is not an event, we wouldn’t normally say that we went to school AFTER it. We would say “Event X occurred AFTER event Y,” not “Event X occurred AFTER event Y had occurred.”</p>
<p>Even though the sentence illustrates that one past event occurred before another past event and it wants to emphasize on the designations (sections) in time, the past perfect is not used.
In grammar, sometimes you can omit (leave out) the verb of a clause. In this case, the phrase “it is” (which would be placed immediately after “although” and before “only two inches long”) is left out. This is called an elliptical construction, or ellipsis. Here are examples of ellipsis:
He plays the violin better than she the piano. [He plays the violin better than she plays the piano.]</p>
<p>He has five dollars; she, four. [He has five dollars; she has four dollars.]</p>
<p>While running, he tripped. He tripped while running. [While he was running, he tripped.]
The sentences in brackets include the omitted words.</p>