Interestingly enough, This is not quite true. In fact, Eph. 1:1-14 is ALL one sentence. And then Eph. 1:14-23 is another long sentence, in Greek. Now, we can't take clause after clause, after clause in English. So translators have had to break up the thought, and put in a bunch of periods at some places, following by a capital. Now, I know someone is going to say, "But the Greek manuscripts don't have punctuation, " and they would be right, they don't! But, what happens here is there is a principle clause in here, somewhere, and the rest of the passage is subordinate clauses. They simply cannot stand alone. So all those relative pronouns, subordinate conjunctions and other ways of making a sentence dependent on a principle clause is written right into the text. Hence, no need for punctuation for the Greeks. As for us - well, we certainly need those periods!
I have never heard anyone actually expound on this topic of why there are such LONG sentences in Ephesians 1. But, as Lynn says here, very important things come out of not isolating verses individually. I have a bunch of Ephesian commentaries. Later, I will take a look, and see what they say about this, if anything.
I do know one thing, we translated this chapter in Greek. Our prof, who seems to be moving towards being a Wesleyan, is firm that predestination is what this chapter is all about. How about this? In context:
"Blessed be the God and Father of our Lord Jesus Christ, who has blessed us in Christ with every spiritual blessing in the heavenly places,4 even as he chose us in him before the foundation of the world, that we should be holy and blameless before him. In love5 he predestined us for adoption to himself as sons through Jesus Christ, according to the purpose of his will,6 to the praise of his glorious grace, with which he has blessed us in the Beloved.7 In him we have redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace,8 which he lavished upon us, in all wisdom and insight9 making known to us the mystery of his will, according to his purpose, which he set forth in Christ10 as a plan for the fullness of time, to unite all things in him, things in heaven and things on earth.11 In him we have obtained an inheritance, having been predestined according to the purpose of him who works all things according to the counsel of his will,12 so that we who were the first to hope in Christ might be to the praise of his glory. 13 In him you also, when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit, 14 who is the guarantee of our inheritance until we acquire possession of it, to the praise of his glory." Eph. 1:3-14
So, I left off the salutation or greeting. But this part is pretty obvious that it is talking about God chose us before the foundation of the earth, having predestined us for adoption, also obtaining an inheritance, having been predestined to the purpose of him who works all things according to the counsel of his will.
It doesn't get much clearer than this! I just see predestined, and all the blessings that entails. I do NOT see any options for some kind of random choice by someone who has not been called by God. Nor do I see anything about the possibilty of resisting God. Or for that matter, losing your salvation, including this myth that once chosen by God, you can just walk away from it. This passage makes it clear, that we were sealed with the promise of the Holy Spirit, who is the guarantee of our inheritance.
And praise God for that!
according to the gospel according to calvin you are a blasphemer... get ye behind me Peter you are an offense to calvinism.. 
