英語の質問に答えます ２

1．　There seem to be no error in his composition.　　(error

2．　A fire broke out, and two-fifths of the city were burnt down. (were

3．　One of the gentleman who was present addressed the public. (was

全部 ()内が誤りなんですが、なぜ誤りかわかりません。
どなたか、解説お願いします。