>>440 7は正解、すまん字数オーバーで切れた。
8.[During my stay in Hokkaido], I often visited the museum.
While(間のニュアンスをはっきり出す) I was staying(進行形が一般的) in Hokkaido, I often visited the museum.
9.I was informed [of his failure in the examination].
I was informed that he failed(事実を知らされてるんだから過去形ね) in the examination.
10.I reminded Hanako [of her having given me a promise].
I reminded Hanako she had gave me a promise.設問の言い回しは変えない
11.[Written in simple English], this book is easy to read.
Because this book is written in simple English, it(繰り返しは避ける) is easy to read.
12.[Taro's winning a tennis championship] pleased us.
It pleased us that Taro won a tennis championship.that節主語では長過ぎる
13.I made a gross mistake [through my carelessness].
I made a gross mistake because I was careless.正解