English has many means by which phrases and clauses may be combined into longer sentences.
A masterful example of this comes from E. B. White:
I spent several days and nights in mid-September with an ailing pig and I feel driven to account for this stretch of time, more particularly since the pig died at last, and I lived, and things might easily have gone the other way round and none left to do the accounting.
At times, such sentence constructions may be very useful. However, just because something can be done, does not mean that it should be.
Much of the trouble that writers get into comes from trying to make one sentence do too much work. Never be afraid to break a long sentence into two short ones, or even three.William Zinsser, On Writing Well, 30th Anniversary Edition.
Over the past few years, I have tried to make more use of multiple shorter sentences rather than longer ones.
This practice comes with the risk of what I call “pronoun drift”.
Consider:
“John sent the report to Dr. George. This was an unprecedented move. He was unsure what should be done next.”
In the second sentence, it should be clear to most readers that “this” refers to the action of sending the report. Without the word “move”, it would be fully clear if it was the report or sending the report that was unprecedented.
In the third sentence, it is unclear if “He” refers to John or Dr. George.
In controlled forms of English, such as ACE, there are rules as to whether the pronoun references the subject or object of a previous sentence.
We do not know if the writer is using such rules, nor if the reader is familiar with them.
It is simpler to replace the pronoun with the name of the party, a distinctive title (e.g. “the doctor”) or some other means that makes the intended meaning clearer.
As an example of long sentences, I cannot think of a better example than H. P. Lovecraft’s “The Shunned House”.
This work is regarded by some as one of Lovecraft’s best short stories.
The work is also notable for some exceptionally long sentences, one of the longest being:
A weak, filtered glow from the rain-harassed street-lamps outside, and a feeble phosphorescence from the detestable fungi within, shewed the dripping stone of the walls, from which all traces of whitewash had vanished; the dank, foetid, and mildew-tainted hard earth floor with its obscene fungi; the rotting remains of what had been stools, chairs, and tables, and other more shapeless furniture; the heavy planks and massive beams of the ground floor overhead; the decrepit plank door leading to bins and chambers beneath other parts of the house; the crumbling stone staircase with ruined wooden hand-rail; and the crude and cavernous fireplace of blackened brick where rusted iron fragments revealed the past presence of hooks, andirons, spit, crane, and a door to the Dutch oven—these things, and our austere cot and camp chairs, and the heavy and intricate destructive machinery we had brought.(142 words!)