Ben's father is said to have been a great athlete.
【= It is said that Ben's father was a great athlete.] (× He is said tha )
(ベンのお父さんはすばらしいスポーツ選手だったそうです。)
I'm sorry not to have answered your e-mail sooner.
(=I'm sorry that I didn't answer your e-mail sooner.」
(メールの返事が遅くなって[←もっと早くあなたのメールに返事しなくて)すみません。)