给定一个英文段落，请编写一个程序，将其中的所有单词首字母大写。


“this is a paragraph. it has multiple sentences. let's make the first letter of each sentence capitalized.”
```
paragraph = "this is a paragraph. it has multiple sentences. let's make the first letter of each sentence capitalized."
capitalized_paragraph = ". ".join([s.capitalize() for s in paragraph.split(". ")])
print(capitalized_paragraph)
```

输出结果为:
```
This is a paragraph. It has multiple sentences. Let's make the first letter of each sentence capitalized.
```