Here are the best options for each blank in the passage:

1. **D. nobody** - "It's hard to believe that nobody had computers a few years ago."
2. **A. paperwork** - "There must have been a lot of paperwork."
3. **C. without** - "how everything worked without computers."
4. **A. a piece** - "Imagine having to find a piece of paper."
5. **B. convenient** - "Sure, it freezes and crashes sometimes. But that's not often. Most of the time my computer is very convenient."

So, the completed passage would read:

"It’s hard to believe that **nobody** had computers a few years ago. I wonder how people lived. There must have been a lot of **paperwork**. I can’t imagine writing everything by hand. I also wonder how everything worked **without** computers. We need computers today for everything. Hospitals, airports, the police... nothing can work without computers. I’m sure I’d be ten times busier than now if I didn’t have a computer. Imagine having to find **a piece** of paper and an envelope and then walking down the street to mail a letter! I love my computer. It makes everything so **convenient**. Sure, it freezes and crashes sometimes. But that’s not often. Most of the time my computer is my best friend."