如何使用 "both" 造句

1. They are both his daddies .
他们都是他的爸爸。
2. It would look better than both .
但又比这两者更好。
3. I believe it was both .
我认为两者都有功。
4. Both positions are firmly held .
双方立场都很坚定。
5. Both companies declined to comment .
两家公司都拒绝发表评论。