Should you ever use “up on”? Similarly, should you ever use “in to”?
Thanks,
Rob
“up on” and “in to” are used when the up or in are a part of a phrasal verb.
He walked up on the crowd. (“walked up” is the verb, synonymous with “approach”, “on” is the preposition, a colloquial variant of “to”)
He walked upon the crowd. (“walked” is the verb, “upon” is the preposition)
He turned the paper in to the professor. (“turn in” is the verb, “to” is the preposition)
He turned the paper into the professor. (“turn” is the verb, “into” is the preposition)
Very different meanings there.
We recently discussed this here.
Never mind, missed a part of a post.
I don’t think this is the question. And BTW it’s a matter of usage, not grammar, to OP. 
What’s the difference between “He put the book on the table.” and “He put the book upon the table.”? It’s merely a matter of emphasis – no, I will not use the character map to put in Gk. but the distinction is subtle, and obvious. Oblivious? Hey I got one consonant (sort of) right.
Well, no, I didn’t give a direct answer, but the implication in my post is yes, you should use “up on” when called for, as it can mean something different from “upon”. Even the stresses when spoken are different.
Upon means atop, almost precisely. You would put books upon the table or the top shelf, but not the bottom shelf – the latter is not inaccurate, but sounds “off” to the hearer. “Up on” implies a vertical lift followed by placement, as in “He [raised the box to eye level and] put it up on the shelf.”
“In to” as two words seems to carry the combined meaning of (a) entrance and (b) movement to a point within. “Arriving at headquarters, the messenger went in to the colonel’s desk.” Into implies entry or penetration.
And of course Bosstone is correct in saying that it’s a usage question, and that phrasal verbs call for the two-word usage. Beware of silliness like “The magician drove home from his show and turned into his driveway.”